Ph.D Michael Schredl
email: michael.schredl@zi-mannheim.de

PhD Leonie Fricke-Oerkermann

MD Alexander Mitschke

Alfred Wiater

MD Gerd Lehmkuhl

Alfred Wiater

MD Ae A Wiater

published or not. The documents may come

Introduction

Nightmares are defined as dreams with strong negative emotions which awaken the dreamer and that are vividly recalled upon awakening [START_REF]Diagnostisches und statistisches manual psychischer sto ¨rungen (DSM IV). Beltz, Go ¨ttingen[END_REF]. They are common during childhood; 70-90% of young adults reported that they experienced nightmares at some time during their childhood [START_REF] Englehart | Punishment, nail-biting and nightmares: a cross-cultural study[END_REF][START_REF] Schredl | Kindheitserinnerungen und Tra ¨ume Erwachsener[END_REF].

The frequency of children suffering from nightmares (often used cutoff: once a week or more) is estimated as being as much as 5% (overview: [START_REF] Schredl | Alptra ¨ume bei Kindern[END_REF]). Many large-scaled surveys [START_REF] Agargun | The prevalence of parasomias in preadolescent school-aged children: a Turkish sample[END_REF][START_REF] Salzarulo | Sleep problems in children and their relationship with early disturbances of the waking-sleeping rhythms[END_REF][START_REF] Simonds | Prevalence of sleep disorders and sleep behaviors in children and adolescents[END_REF][START_REF] Vela-Bueno | Prevalence of night terrors and nightmares in elementary school children: a pilot study[END_REF] are based on questionnaires or interviews completed by the child's parents. Several studies [START_REF] Lapouse | An epidmiologic study of behavior characteristics in children[END_REF][START_REF] Mindell | Nightmares and anxiety in elementary-aged children: is there a relationship?[END_REF][START_REF] Muris | Fears, worries, and scary dreams in 4-to 12-year-old children: their content, developmental pattern, and origins[END_REF][START_REF] Owens | Sleep habits and sleep disturbance in elementary school-aged children[END_REF][START_REF] Paavonen | Sleep problems of school-aged children: a complementary view[END_REF][START_REF] Richman | Surveys of sleep disorders in children in a general population[END_REF], however, reported a marked underestimation of nightmare occurrence in the parents' responses in comparison to the answers of the child, so that epidemiological studies based on data obtained from the parents have to be interpreted with caution. Lapouse and Monk [START_REF] Lapouse | An epidmiologic study of behavior characteristics in children[END_REF], for example, reported an exact agreement for the occurrence of nightmares of 54%, in 17% the parents' j Abstract Objective The present study investigated the relationship between daytime symptomatology and nightmare frequency in school-aged children by eliciting daytime symptoms and nightmare frequency from children directly in addition to questionnaires completed by their parents. Methods A sample of 4,834 parents and 4,531 of their children (age range: 8-11 years) completed each a sleep questionnaire and the strengths and difficulties questionnaire (SDQ).

Results

The results of the study clearly indicate that there is an underestimation of nightmare frequency in the parents' ratings compared to the children's data (effect size: d = 0.30) and the closeness between influencing factors and nightmare frequency is considerably higher for the data based on the children's responses; the proportion of explained variance was twice as high. Conclu- sions Therefore, it seems important for research and clinical practice to not to rely on parents' information but to ask the children about the occurrence of nightmares.

j Key words nightmareschildren responses were positive and the children's responses negative and 30% of the children reported having nightmares whereas the parents indicated no nightmares. Muris et al. [START_REF] Muris | Fears, worries, and scary dreams in 4-to 12-year-old children: their content, developmental pattern, and origins[END_REF] carrying out interviews with children aged 4-12 and their parents separately reported that the agreement is quite good in the youngest age group (4-6 years) but considerable underestimation was present in the older children. For nightmares this seems plausible since nightmares do not occur in a setting supervised by the parents (own bedroom, second half of the night) and the majority of children in the age group of 10-16 years reported in a study that they try to forget the bad dream and did not talk about it with her/his parents [START_REF] Schredl | Geschlechtsspezifische Unterschiede in Angsttra ¨umen von Schu ¨lerinnen und Schu ¨lern[END_REF].

The common model in the etiology of nightmares implies an interaction between disposition (genetic factors; [START_REF] Hublin | Nightmares: familial aggregation and association with psychiatric disorders in a nationwide twin cohort[END_REF]; personality; [START_REF] Hartmann | Boundaries in the mind[END_REF]; trait anxiety, [START_REF] Mindell | Nightmares and anxiety in elementary-aged children: is there a relationship?[END_REF]) and acute stressors [START_REF] Schredl | Effects of state and trait factors on nightmare frequency[END_REF] and trauma (kidnapping: [START_REF] Terr | Psychic trauma in children: observations following the Chowchilla schoolbus kidnapping[END_REF][START_REF] Terr | Chowchilla revisited: the effects of psychic trauma four years after a schoolbus kidnapping[END_REF]; war experiences: [START_REF] Valli | The threat simulation theory of the evolutionary function of dreaming: evidence from dreams of traumatized children[END_REF]; natural disasters: [START_REF] Dollinger | Lightning-strike disaster among children[END_REF]; severe burns: [START_REF] Stoddard | Dreams and nightmares of burned children[END_REF]). Most of the studies investigating the relationship between trait anxiety or psychopathological symptoms, however, are based on data obtained from the parents (cf. [START_REF] Achenbach | The child behavior profile: I. boys aged 6-11[END_REF][START_REF] Achenbach | The child behavior profile: II. boys aged 12-16 and girls aged 6-11 and 12-16[END_REF][START_REF] Conners | Symptom pattern in hyperkinetic, neurotic and normal children[END_REF][START_REF] Miller | Dimensions of psychopathology in middle childhood[END_REF][START_REF] Miller | Loisville behavior check list for males, 6-12 years of age[END_REF][START_REF] Miller | Revised anxiety scales for the Louisville behavior check list[END_REF][START_REF] O'donnell | Dimensions of behavior problems in Anglo-American and Mexican-American preschool children: a comparative study[END_REF]). Mindell and Barrett [START_REF] Mindell | Nightmares and anxiety in elementary-aged children: is there a relationship?[END_REF], for example, demonstrated that the relationship between trait anxiety and nightmare frequency was only present in the data reported by the children but not in the data reported by the parents; a finding that might be associated with the underestimation of nightmare occurrence in parents.

The present study investigated the relationship between daytime symptomatology and nightmare frequency in school-aged children by eliciting daytime symptoms and nightmare frequency from the children directly in addition to questionnaires completed by parents. First, an underestimation of nightmare frequency by parents was expected. Secondly, it was predicted that the relationship between nightmare frequency and daytime symptomatology is more pronounced in the data obtained from the children than within the dataset obtained from the parents.

Method j Participants

Overall, 8,599 children of the forth grade in all schools of the city of Cologne (with the exception of two schools (N = 74) and their parents were asked to participate in the present study. 4,834 parents responded; the response rate was 56%. The mean age of the total sample was 9.49 ± 0.61 years (range: 8-11 years). The small difference in the mean age of boys (N = 2,318) and girls (N = 2,516) was statistically significant (9.50 ± 0.62 [boys] vs. 9.46 ± 0.60 [girls], t = 4.1, P < 0.0001). 303 children did not complete their questionnaires. i.e., in 4,531 cases data from parents and their respective child were available for analyses.

Materials j Sleep questionnaire (parents and child version)

For the purpose of the study, a sleep questionnaire for children (28 items) and a parental questionnaire (33 items) were developed. The items followed a threepoint format (1 = not present, 2 = sometimes, 3 = often). Several areas concerning sleep and related-waking behavior were elicited. Nightmare frequency was measured as follows: ''I have nightmares.'' and ''My child has nightmares that she/he remembers.'' Other items measure problems at sleep onset, problems of maintaining sleep, watching TV prior to bedtime, night terrors and sleep walking (the latter two only in the parents), playing computer games prior to bedtime (only child version), stress in the family. Night terrors were defined as sudden cries during the night and without recollection of the event by the child.

j Strengths and difficulties questionnaire SDQ (parents and child version)

Both versions of the instrument consisted of five 5items subscales that assess conduct problems (e.g., often lies or cheats), hyperactivity-inattention (e.g., constantly fidgets and squirms), emotional symptoms (e.g., nervously clingy in new situations), peer problems (e.g., rather solitary, tends to play alone), and prosocial behavior (e.g., considerate of other people's feelings; [13,[START_REF] Goodman | Psychometric properties of the strengths and difficulties questionnaire[END_REF]). A three-point response format was used to record respondents' level of agreement that the item described the child's behavior of the past 6 months. Scores are allocated on the basis of 0 for items checked as being ''not true'', 1 for items checked as being ''somewhat true,'' and 2 for items checked as ''certainly true.'' A small number of negatively worded items were reverse scored. Each of the five subscales is obtained by adding the responses to the constituent items (range: 0-10), and a total difficulties score (range 0-40) is obtained by adding the scores for all but the prosocial subscale. Reliability coefficients for the total score and the subscales were high: internal consistency coefficients ranged from r = 0.60 to r = 0.87 and retest reliabilities (4-6 months retest interval) were also within that range from r = 0.51 to r = 0.80 [START_REF] Goodman | Psychometric properties of the strengths and difficulties questionnaire[END_REF]. The fairly high interinformant correlations (teacher, child, parent, other children) ranging from r = 0.30 to r = 0.43 suggest that the SDQ is a sound measurement instrument [START_REF] Mellor | Furthering the use of the strengths and difficulties questionnaire: reliability with younger child respondents[END_REF].

j Design and procedure

In all schools of Cologne (school type ''Grundschule''), teachers distributed the information, written consent forms, and the questionnaires to the children of the fourth grade. The questionnaires (coded with identical numbers) were completed by the child and his/her parents separately at home and returned to the teacher. The questionnaire data were coded and analyzed with the statistical software package SAS for Windows 8.02. The rating scales were analyzed by nonparametrical methods (Sign Rank test and Spearman Rank correlations) given the three-point ordinal nightmare scale. One-tailed tests were applied if the hypothesis was directed. Effect sizes based on formula given in Rosenthal [START_REF] Rosenthal | Parametric measures of effect size[END_REF] were calculated because in large samples even very small effects reach statistical significance and the effect size is independent from sample size and, thus, comparable to other findings.

Results

j Nightmare frequency About 2.3% of the parents indicated that their child often has nightmares, whereas about 26.9% checked the ''sometimes'' category (Table 1). For the children's ratings, the values are higher: 3.5% of the sample stated that nightmares occur often and 40% stated that they occur sometimes. The difference between the two measures was statistically significant (Sign Rank test: S = 213550.5, P < 0.0001). The effect size for the difference in percentages concerning the often category (3.5% vs. 2.3%) amounted to d = 0.07; for the collapsed data (sometimes and often) the difference (43.5% vs. 29.2%) the effect size was d = 0.30. The intercorralation between the items was fairly high (r = 0.474, P < 0.0001). For comparison, the intercorrelation coefficients for the SDQ subscales varied between r = 0.535 (prosocial behavior) and r = 0.704 (hyperactivity).

In order to study the possible effect of occurrence of night terrors on the discrepancy between parental data and children's data regarding nightmare frequency, the night terror ratings of the group with parental ratings lower than the children's ratings regarding nightmare frequency (night terrors: often: 0.82%, sometimes: 6.39%, not present: 92.78%, N = 970) were compared to the rest of the group (night terrors: often: 0.70%, sometimes: 4.50%, not present: 94.80%; N = 3,848). The difference was significant (v 2 = 6.2, P = 0.0449, effect size: d = 0.089), i.e., in cases children reported nightmares whereas the parents did not, parents significantly more often reported that their children had night terrors. j Correlations with nightmare occurrence For both measures, nightmares occurred slightly more often in girls than in boys (parents' ratings: often: 2.7%, sometimes: 29.0%, not present: 68.3% [girls] vs. often: 2.3%, sometimes: 25.2%, not present: 72.5% [boys], z = 4.1, P = 0.0015; children's ratings: often: 4.0%, sometimes: 41.9%, not present: 54.1% [girls] vs. often: 3.1%, sometimes: 38.7%, not present: 58.3% [boys], z = 3.0, P = 0.0030).

Problems falling asleep, problems maintaining sleep and other parasomnias like sleepwalking and night terrors were significantly associated with the occurrence of nightmares (see Table 2). Sleep problems were significantly closer associated for the children's data in comparison to the data obtained by parents. All four problem scores and the total score of the strength and difficulties questionnaire (SDQ) were positively related to nightmare occurrence (see Table 2). Again, the associations were stronger for the j Logistic regression for nightmare occurrence

Due to the format of the nightmare scale (three-point ordinal format) logistic regressions have been computed. The proportion of explained variance for the parents' data was 7.75%, with significant effects of all five SDQ subscores. The model for the children's data yielded a higher proportion of explained variance (16.23%), with significant effects of the emotional symptoms score, the conduct problems score and the peer problems score (Table 3).

Discussion

The results of the study clearly indicate that there is an underestimation of nightmare frequency in the parents' ratings compared to the children's data and the closeness between influencing factors and nightmare frequency is considerably higher for the data based on the children's responses. First, the difference between parents' and children's estimates regarding the occurrence of nightmares was of small to medium effect size (often category: d = 0.07 and often and sometimes combined: d = 0.30). For the prevalence rates, the often category was 50% more often reported by children than by parents (3.5% vs. 2.3%), so that large-scaled surveys based solely on parents' data clearly underestimate the occurrence of nightmares in children.

The absolute prevalence rates obtained in this study lies within the range of figures reported in the literature, nevertheless immediate comparison to other studies is not possible because each study used different definitions of nightmares, for example, [START_REF] Agargun | The prevalence of parasomias in preadolescent school-aged children: a Turkish sample[END_REF] applied the complete criteria of the nightmare disorder of the DSM IV [START_REF]Diagnostisches und statistisches manual psychischer sto ¨rungen (DSM IV). Beltz, Go ¨ttingen[END_REF]. In addition, answering cate-gories differed across the studies: In this study sometimes/often were presented to the participants whereas in the Simonds and Parraga [START_REF] Simonds | Prevalence of sleep disorders and sleep behaviors in children and adolescents[END_REF] study the cutoff was once a week. A topic discussed in the recent literature is the awakening criterion in the definition of nightmares [START_REF] Blagrove | Evaluating the awakening criterion in the definition of nightmares: how certain are people in judging whether a nightmare woke them up?[END_REF], i.e., whether the dreamer explicitly states that he/she wakes up because of the dream. It is still debated whether nightmares with awakening differ regarding their correlations with waking-life variables from bad dreams (disturbing dreams without awakening, cf. [START_REF] Blagrove | Evaluating the awakening criterion in the definition of nightmares: how certain are people in judging whether a nightmare woke them up?[END_REF][START_REF] Zadra | Nightmares and bad dreams: their prevalence and relationship to well-being[END_REF]). This research, however, was limited to adults only. Interestingly, Schredl and Pallmer [START_REF] Schredl | Geschlechtsspezifische Unterschiede in Angsttra ¨umen von Schu ¨lerinnen und Schu ¨lern[END_REF] asking for the most recent bad dream obtained many reports of typical nightmares (falling, being chased) where the dream action is terminated by awakening, e.g., by waking up before touching the ground or before the persecutor is reaching the dreamer. One might speculate that the terms nightmare/bad dream/disturbing dream are somewhat interchangeable, at least in children studies. For comparing results from epidemiological studies, however, it will be necessary to use standard criteria for the definition of nightmares (vivid, good recall upon awakening, mostly in the second half of the night) and comparable answering categories (e.g., once a week etc.).

Since the items were slightly differently worded (parental questionnaire included ''that she/he remembers''), it was studied whether the child might overestimate nightmare frequency due to mistaken night terrors for nightmares (which could only have happened if the parents or other family members told the child about the night terrors because the child itself is amnesic for the attacks in most of the cases, cf., [START_REF] Ferber | Sleepwalking, confusional arousals and sleep terrors in children[END_REF]). There was a small but significant effect, i.e. parents who underestimate the nightmare frequency in comparison to their child more often reported night terrors. But the small effect size (d = 0.089) and the small difference in percentages between the two groups of parents (underestimating vs. others) can only partly explain the difference between children's and parents' responses because the difference in nightmare ratings is larger (d = 0.30). On the other hand, it might be an alternative explanation that children tend to overestimated the occurrence of nightmares due to, for example, being susceptible to a recent very vivid nightmare or an affirmative response bias for the positively formulated questionnaire items. Based on the findings of Schredl and Pallmer [START_REF] Schredl | Geschlechtsspezifische Unterschiede in Angsttra ¨umen von Schu ¨lerinnen und Schu ¨lern[END_REF] that children in this age group often do not talk about their nightmares, it seems plausible that the lower prevalence rates reported by parents might be a consequence of the child's reluctance to report nightmares. This line of thinking is supported by the SDQ data provided by Mellor [START_REF] Mellor | Furthering the use of the strengths and difficulties questionnaire: reliability with younger child respondents[END_REF]. He reported that parent-child discrepancies were minimal for the hyperactivity scale but considerably high for the emotional symptom scores (with parents' rating being lower on average). One might hypothesize that ''internal'' symptoms might be underestimated by parents if the children don't talk about them but this is not the case for observable behavior like hyperactivity (the highest parent-child intercorrelation in this study was found for the hyperactivity subscale). Therefore, it seems important for research as well as clinical practice (cf. [START_REF] Fricke | Schlafsto ¨rungen im Kindes-und Jugendalter: Ein Therapiemanual fu ¨r die Praxis[END_REF]) not to rely only on information obtained from parents but to ask the children about the occurrence of nightmares directly.

As reported in previous studies, nightmare frequency was related to the occurrence of other parasomnias (e.g., [START_REF] Fisher | Selected sleep disturbances in school children reported by parents: prevalence, interrelationships, behavioral correlates and parental attributions[END_REF][START_REF] Schredl | Nightmares in children: influencing factors[END_REF]), sleep problems (e.g., [START_REF] Fisher | Do diagnostic patterns exist in the sleep behaviors of normal children[END_REF][START_REF] Paavonen | Sleep problems of school-aged children: a complementary view[END_REF]) and waking-life psychopathology (see introduction). The highest correlation was found for the emotional problems score of the SDQ which encompasses the occurrence of headaches, worries, anxieties and being unhappy and nervous. Comparing sizes of correlation coefficients and the coefficients derived from the logistic regression, the emotion symptoms subscale yielded substantial effect whereas the other factors are of minor importance despite their statistical significance due to large sample size. Expanding the research in adults (e.g., [START_REF] Levin | Nightmare prevalence, nightmare distress, and self-reported psychological disturbance[END_REF][START_REF] Schredl | Effects of state and trait factors on nightmare frequency[END_REF]), it would be interesting to study whether factors like fantasy proneness, psychological absorption, dysphoric imaginative involvement, everyday stress is also related to nightmare frequency in children.

Although the overall pattern of influencing factors was fairly similar, the correlation coefficients for the factors were significant larger for the children's ratings compared to the coefficients based on the parents' data; the proportion of explained variance (logistic regressions) was twice as high (16.23% vs. 7.75%). This underlines the importance of using children's data in research regarding nightmare etiology. Overall, more research is needed looking into the discrepancies between children's and parents' ratings regarding the occurrence of nightmares in order to support the hypothesis of Schredl and Pallmer [START_REF] Schredl | Geschlechtsspezifische Unterschiede in Angsttra ¨umen von Schu ¨lerinnen und Schu ¨lern[END_REF] that non-reporting is the major underlying factor in the parental underestimation. This might also play a role in other sleep complaints (the data regarding sleep disorders of this sample are presented elsewhere [START_REF] Wiater | Sleep disorders and behavioural problems among 8-to 11-year-old children[END_REF]). One might also speculate that the child's estimates of nightmare frequency or daytime behavior might be biased or deficient, which means that more sophisticated methods of eliciting these variables are necessary, e.g., interviews or sleep diaries.

Table 1

 1 Nightmare occurrence

	Children	Not present	Sometimes	Often	Total
	Parents
	Not present 50% (2,264) 18.9% (850) 1.4% (62) 70.9% (3,176)
	Sometimes 5.2% (235)	20.3% (908) 1.4% (62) 26.8% (1205)
	Often	0.5% (21)	1.1% (47)	0.8% (34) 2.3% (102)
	Total	56.2% (2520) 40.3% (1805) 3.5% (158) 100% (4483)
	Spearman rank correlation: r = 0.474 (P < 0.0001)

*** 0.308*** z = )8.8, P < 0.0001 ***P < 0.0001 (Spearman rank correlations) a Comparing the magnitude of the correlation coefficients

Table 3

 3 Logistic regression (cumulative logit model) for nightmare occurrence

	Variable	Parents		Children
		Standard	v 2 test, Probability	Standard	v 2 test, Probability
		estimate		estimate
	SDQ scales
	Emotional symptoms	0.263	175.2, P < 0.0001	0.370	315.6, P < 0.0001
	Hyperactivity-inattention	)0.059	7.9, P = 0.0049	0.003	0.0, P = 0.8860
	Conduct problems	0.067	9.6, P = 0.0019	0.096	21.1, P < 0.0001
	Peer problems	0.055	7.8, P = 0.0053	0.050	6.4, P = 0.0116
	Prosocial behavior R 2 (max. rescaled)	0.075 0.0775	13.9, P = 0.0002	0.012 0.1623	0.4, P = 0.5244

Factors affecting nightmares in children


Dr Kathrin Sevecke
email: kathrin.sevecke@uk-koeln.de

MD Gerd Lehmkuhl

Maya K Krischer

Ae M K Krischer

Keywords:

Examining relations between psychopathology and psychopathy dimensions among adolescent female and male offenders

j Abstract Aim This study was performed to investigate relations between psychopathology and psychopathy in adolescent female and male detainees. Method We examined 91 male and 123 female adolescent detainees (aged [START_REF] Cooke | Psychopathy across cultures: North America and Scotland compared[END_REF][START_REF] Cooke | Refining the construct of psychopathy: towards a hierarchical model[END_REF][START_REF] Corrado | Predictive validity of the psychopathy checklist: youth version for general and violent recidivism[END_REF][START_REF] Crick | Relational aggression, gender, and socialpsychological adjustment[END_REF][START_REF] Dembo | Gender differences in mental health service needs among youths entering a juvenile detention centre[END_REF][START_REF] Doepfner | Reliability and factorial validity of the YSR and CBCL[END_REF] for psychopathology -using the Youth Self Report, the Overt Aggression Scale-Modified and a Conduct Disorder Self Report Scale-and for psychopathic dimensions using the psychopathy checklist youth version (PCL:YV). Based on a linear regression analysis we compared the specific associations between psychopathology and psychopathy in both male and female delinquent juveniles. Results Our results revealed higher scores for externalizing behavior and psychopathic dimensions in delinquent males, and higher internalizing problem scores in delinquent females. Furthermore, we found a positive relationship between suicidal behavior and the psychopathy total score as well as the affective, the lifestyle and the antisocial dimension only in girls. No association was found for suicidal behavior in boys. Regarding anxious-depressive behavior, we found a negative relation to the psychopathy total score and to the affective psychopathy factor for the boys. Conclusion Expectedly, the population of incarcerated adolescents exhibited a high prevalence of psychopathology. At the same time our results referred to meaningful gender-related differences with respect to associations with psychopathy. The gender-related differences in psychopathological symptoms could indicate varied subtypes of psychopathy in boys and girls.

Introduction j Delinquency and psychopathology

Recent studies with juvenile delinquents have emphasized the overlap between delinquency and psychopathology, such as depression, suicidality, anxiety, posttraumatic stress disorder (PTSD), conduct disorder (CD), substance use disorder and attention deficit hyperactivity disorder (ADHD) [START_REF] Vermeiren | Mental health problems in juvenile justice populations[END_REF]. Various research groups have not only recognized a high prevalence of Externalizing (Ext) symptomatology, but also Internalizing (Int) psychopathology in delinquent youth [START_REF] Haapasalo | Childhood family problems among young violent and property offenders[END_REF][START_REF] Teplin | Psychiatric disorders in youth in juvenile detention[END_REF][START_REF] Vermeiren | Antisocial behaviour and mental health. Findings from three communities[END_REF][START_REF] Vermeiren | Predicting recidivism in delinquent adolescents from psychological and psychiatric assessment[END_REF][START_REF] Vermeiren | Psychopathology and delinquency in adolescents: a descriptive and developmental perspective[END_REF]. Comorbidity of mental health disorder is estimated to be present in more than half of criminal adolescents [START_REF] Vermeiren | Psychopathology and delinquency in adolescents: a descriptive and developmental perspective[END_REF]. Authors have repeatedly emphasized the need to perform more research on the coexistence of comorbid disorders in adolescents, and on the need for more research on female juvenile delinquents, since female delinquency is a comparatively new phenomenon [START_REF] Odgers | Aggressive and antisocial girls: research update and challenges[END_REF][START_REF] Patrick | Psychopathy and externalizing: genetics and brain function. Invited address. Conference on ''developmental and neuroscience perspectives on psychopathy[END_REF]. The few studies with females have described them as more likely to have a history of previous psychiatric help than criminal males and to be more often referred to mental health services when delinquent [START_REF] Dembo | Gender differences in mental health service needs among youths entering a juvenile detention centre[END_REF][START_REF] Thomas | A comparison of correctional and mental health referrals in the juvenile court[END_REF]. In comparison with male criminal offenders, female delinquents were shown to endure more severe emotional and behavioral problems [START_REF] Kataoka | Mental health problems and service use among female juvenile offenders: their relationship to criminal history[END_REF][START_REF] Timmons-Mitchell | Comparing the mental health needs of female and male incarcerated juvenile delinquents[END_REF].

j Psychopathy in youth

An increasing body of literature focuses on psychopathy in incarcerated youth, but to our knowledge none of these studies addresses the relationship of psychopathy and psychopathology comparing males and females. Within the literature on psychopathy, some scholars have postulated that the disorder comprises distinct facets including interpersonalaffective traits (e.g. superficial charm, manipulativeness, lack of empathy) and antisocial traits (like impulsivity and aggression) [START_REF] Cooke | Refining the construct of psychopathy: towards a hierarchical model[END_REF][START_REF] Hare | The Hare psychopathy checklist-revised, 2nd edn[END_REF]. Factor analyses have recently examined these latent dimensions and described them as interpersonal (F1), affective (F2), lifestyle (F3), and antisocial features (F4) [START_REF] Forth | The Hare psychopathy checklist: youth version[END_REF]. Interpersonal and affective features were described as the core factors of the ''psychopathic personality'' [START_REF] Cleckley | The mask of sanity[END_REF][START_REF] Hare | Without conscience: the disturbing world of the psychopaths among us[END_REF] and research with adults suggested that these were the most distinctive and defining aspects of the disorder [START_REF] Cooke | An item response theory analysis of the Hare psychopathy checklist[END_REF]. Studies with male offenders [START_REF] Boldt | A multigroup item response theory analysis of the psychopathy checklist-revised[END_REF][START_REF] Cooke | An item response theory analysis of the Hare psychopathy checklist[END_REF][START_REF] Cooke | Psychopathy across cultures: North America and Scotland compared[END_REF] examined the item response theory (IRT) to test item functioning and concluded that the interpersonal/affective dimension was generally more discriminating and provided more information about the construct than behavioral items. Vincent and Hart utilized the IRT with adolescent boys: Their findings indicated that psychopathy in adolescent boys was a coherent construct and that there were some similarities in item functioning between male adolescents and adults [START_REF] Vincent | Psychopathy and Youth[END_REF]. Corrado et al. [START_REF] Corrado | Predictive validity of the psychopathy checklist: youth version for general and violent recidivism[END_REF] showed in their prospective study (average 14.5 months follow-up) with adolescent male offenders that both the two-factor and three-factor model of the PCL:YV significantly predicted general and violent recidivism at a predictive accuracy ranging from 68 to 63%. However, unlike results with adult samples, regression analyses indicated these associations were explained primarily by behavioral psychopathic symptoms rather than interpersonal or affective traits. The study of Murrie et al. [START_REF] Murrie | Youth with psychopathy features are not a discrete class: a taxometric analysis[END_REF] yielded consistent evidence that the psychopathy construct has a dimensional latent structure among male ado-lescents (n = 757). Although youth clearly varied in the degree to which they manifested psychopathy-like personality traits they found that there was no natural, discrete class of young ''psychopaths''.

j Psychopathy across gender

The psychopathy construct is believed to exist in male and female adults, moreover there is a controversial discussion about psychopathy in women, and the potential downward extension to girls [START_REF] Schrum | Psychopathy in adolescent female offenders: an item response theory analysis of the psychopathy checklist: youth version[END_REF]. The psychopathy checklist-revised (PCL-R) [START_REF] Hare | The Hare psychopathy checklist-revised, 2nd edn[END_REF] used for adult female offenders found lower means and a lower prevalence of psychopathy in female prisoners than in incarcerated men [54,[START_REF] Salekin | Psychopathy and recidivism among female inmates[END_REF][START_REF] Vitale | Using the psychopathy checklist-revised with female samples: reliability, validity, and implications for clinical utility journal of clinical psychology[END_REF]. In fact, among male offenders it has been demonstrated that psychopathy predicted violent recidivism [START_REF] Grann | Psychopathy (PCL-R) predicts violent recidivism among criminal offenders with personality disorders in Sweden[END_REF][START_REF] Hare | Psychopathy and the predictive validity of the PCL-R: an international perspective[END_REF][START_REF] Lewis | Predictors of violent recidivism in juvenile offenders[END_REF]; in female offenders, however, the PCL-R predicted violent recidivism only moderately [START_REF] Salekin | Psychopathy and recidivism among female inmates[END_REF]. Two recent studies found that among incarcerated adolescent females PCL:YV scores were not predictive of future offending [START_REF] Odgers | Examining the science and practice of violence risk assessment with female adolescents[END_REF][START_REF] Vincent | Predictive validity of the psychopathy checklist: youth version for recidivism with female adolescent offenders[END_REF]. The study of Welsh et al. [82] examined the predictive and incremental validity in a male and female adolescent sample of three instruments used in youth risk assessments: The structured assessment of violence risk in youth (SAVRY) offered the most incremental predictive validity for general recidivism and violent recidivism whereas the PCL:YV followed closely behind.

j Psychopathy and psychopathology

Studies with male delinquent adults and adolescents have found that psychopathy carries significant comorbidity with a number of psychiatric disorders, including ADHD [START_REF] Abramowitz | The relationship between childhood attention-deficit hyperactivity disorder and conduct problems and adult psychopathy in male inmates[END_REF]42,[START_REF] Lynam | Early identification of the fledging psychopath: locating the psychopathic child in the current nomenclature[END_REF], depression [START_REF] Mealey | The sociobiology of sociopathy: an integrated evolutionary model[END_REF], traumarelated disorders [START_REF] Weiler | Psychopathy and violent behaviour in abused and neglected young adults[END_REF] and anxiety [START_REF] Kosson | The reliability and validity of the psychopathy checklist-youth version in nonincarcerated males[END_REF] and that psychopathy features exhibit divergent phenotypic relations with Int and Ext psychopathology [START_REF] Benning | Estimating facets of psychopathy from normal personality traits: a step toward community epidemiological investigations[END_REF][START_REF] Patrick | Psychopathy and externalizing: genetics and brain function. Invited address. Conference on ''developmental and neuroscience perspectives on psychopathy[END_REF]. Prior North American studies with the PCL:YV have shown that incarcerated adolescent males with high PCL:YV scores display an elevated prevalence of a variety of Ext behaviors, including more aggressiveness [START_REF] Gretton | Predicting patterns of criminal activity in adolescent sexual psychopaths[END_REF], more CD symptoms, and greater alcohol and substance abuse compared to low-scoring adolescent males [START_REF] Forth | Psychopathy in adolescence: assessment, violence and developmental precursors[END_REF]. In contrast to Ext disorders Int disorders are often assumed to vary inversely with psychopathic traits. The relationship between suicidal behaviors and adult psychopathy i.e., has been examined only in a few studies. Whereas Cleckley argued that suicidal behaviour in psychopathic individuals was generally manipulative, studies of psychopathic inmates have sometimes reported positive correlations between psychopathy and suicide attempts [START_REF] Stafford | Psychopathy scores predict adolescent inpatient aggression[END_REF][START_REF] Verona | Psychopathy, antisocial personality, and suicide risk[END_REF][START_REF] Verona | Psychopathy and suicidality in female offenders: mediating influences of personality and abuse[END_REF]. To our knowledge, there is only one study which has examined self-directed aggression and psychopathic traits in adolescents. Gretton et al. [START_REF] Gretton | Psychopathy and offending from adolescence to adulthood: A 10year follow-up[END_REF] reported that offenders with high scores on the PCL:YV were more likely to have a history of self-injury than those with low scores. However, correlations between psychopathic traits and suicidal tendencies were significant only for females.

j Study hypotheses

This study intends to focus on the specific differences in female and male juvenile offenders regarding the relationship between psychopathy dimensions and concurrent psychopathology. Our hypotheses were: 1.) We expected higher rates of dimensional measurements of internalizing psychopathology in incarcerated girls than in incarcerated boys and higher rates of dimensional measurements of externalizing psychopathology in incarcerated boys than in girls. We predicted (2.) gender differences in the associations between externalizing and internalizing and the underlying psychopathy structure: For boys we expected a positive relation between externalizing and all psychopathy dimensions and no or a negative relation between internalizing and the interpersonal and the affective dimensions (the psychopathy core factors). For girls, we expected a positive relation between externalizing and all psychopathy dimensions, no or a negative relation between internalizing and all psychopathy dimensions; at the same time we hypothesized a positive relation between suicidal behavior and the lifestyle as well as the antisocial dimension (behavioral factors of psychopathy) for girls.

j Materials and methods

Subjects

The present study was conducted as part of the Cologne GAP-Study (Gewalt = violence; Aggression = aggression; Perso ¨nlichkeit = personality), an investigation of personality pathology, violence and aggression in adolescents. The sample for this study consisted of 214 incarcerated juveniles (91 boys and 123 girls), aged 14-19 years. Because in Germany the age of criminal responsibility starts at the age of 14, we selected youth of at least 14 years of age. The boys had a mean age of 17.73 years (SD = 1.19; range = 14-19), the girls a mean age of 17.67 years (SD = 1.30; range = 14-19). The male and female samples did not differ on age (T = )0.34; P = 0.74). The participants were incarcerated in two German jails, located in the Cologne-Bonn area, North Rhine Westphalia, Germany. 68.4% of all participants had been sentenced for committing at least one violent criminal act; while 31.6% had no violent conviction. Broken out by gender, 42.1% of the girls had never been convicted of a violent crime, compared to only 17.6% of the delinquent boys. On average the boys in our sample had 2.3 violent convictions (SD = 1.9), while the girls only had 1.2 (SD = 1.52, T = )4.7, P < 0.001). The mean number of prior violent and non-violent convictions in our sample was 3.5 (SD = 3.2), and sample members were on average incarcerated for the second time (SD = 1.7). Again, the girls differed from the boys, recording 2.5 convictions (SD = 2.3, T = )5.4, P < 0.001) and 1.8 incarcerations, (SD = 1.3, T = )3.3, P = 0.001) compared to 4.9 convictions (SD = 3.7) and 2.5 detentions (SD = 2.0) for the boys. The juveniles who participated in our study were detained on average for 10.4 months (SD = 11.6). The data regarding criminal behavior was based on file information.

As for the ethnic composition of the sample, racial distribution of participants across sex was equivalent. The sample consisted of 80.8% Caucasian/Germans, 2.3% Turkish/Arabs, 3.7% Russian-Germans, 2.3% Africans, and 8.6% of other ethnic backgrounds (such as Polish, Rumanian, Ukrainian) (v 2 = 8, P = 0.24). Comparing the upbringing and family factors of the delinquent adolescents there was no difference in the frequency of divorce or separation of parents among the female (59.9%) and male (58.3%) adolescents (v 2 = 5.28, P = 0.15). 64.2% of the girls reported a history of having lived in foster care and 19.5% on welfare during upbringing; the boys showed no difference, with 54.9% having lived in foster care (v 2 = 3.62, P = 0.46) and 27.5% having lived on welfare (v 2 = 7.88, P = 0.25).

j Procedure

Prior to testing, all participants were oriented to the administration protocol and the nature of the procedure. Under German law parental consent is not required with respect to juvenile matters that involve minimal risk; because all participants were 14 years of age or older, the Legal Administration of Data Protection of the University of Cologne waived parental consent, and the Institutional Review Board of the University Clinic of Cologne gave approval for the current study. Verbal and written explanations of the study were provided to youth prior to testing, and youth were advised that study participation was voluntary. All subjects were informed that they could withdraw their informed consent at any time during and after testing. If subjects had difficulty understanding procedures, additional explanation was provided. After receiving informed consent, subjects were interviewed. Legal information such as the legal status of the participant, the number of convictions and length of stay were collected from file information. The protocol excluded juveniles with a schizophrenic spectrum diagnosis, or who were under the acute influence of alcohol or other drugs, or who had an IQ lower than 70, determined by a standardized German clinical interview for children and juveniles according to ICD-10 (DISYPS) [START_REF] Doepfner | Diagnostik-System fu ¨r Psychische Sto ¨rungen im Kindes-und Jugendalter nach ICD-10 und DSM-IV (DISYPS-KJ)[END_REF] and by subtests of the Wechsler Adult Intelligence Test [START_REF] Wechsler | A comparative study of adolescent risk assessment instruments: predictive and incremental validity[END_REF].

j Measures

Psychopathy checklist youth version (PCL:YV)

The juveniles' personalities were assessed with the PCL:YV [START_REF] Forth | The Hare psychopathy checklist: youth version[END_REF], a multi-item symptom construct rating scale that measures interpersonal and affective characteristics as well as overt behaviors. Trained observers rate the severity of each item based on a semi structured interview, a review of case history information, and behavioral observation crosschecked with collateral informants. Scores of 0 (consistently absent), 1 (inconsistent), or 2 (consistently present) for each item of the PCL:YV reflect inferences about the consistency of the specific tendency or disposition across different situations. The interview, developed by Forth et al. to assess youth psychopathy, was translated using a forward-backward method and adapted by the authors to the German language, school and legal system [START_REF] Forth | The Hare psychopathy checklist: youth version[END_REF][START_REF] Sevecke | The German version of the psychopathy checklist-youth version (PCL:YV)[END_REF].

The PCL:YV assessments were carried out by four specially trained professionals with at least masterlevel education and long-term clinical experience. They received extensive training in giving and rating the PCL:YV before conducting the interviews and assessed at least 5 subjects together with one of the two trainers. Afterwards, interrater reliability was reexamined every 10-15 interviews. It was calculated in several ways. First, we compared the single scores of all 20 items and reached a kappa score between 0.52 and 0.89. Second, PCL:YV total scores were compared, resulting in a kappa score between 0.80 and 0.92. The interrater reliability for the males was also compared with that for the females. The interrater reliability for the males/females regarding the single item scores reached a kappa between 0.66-0.90/0.55-0.79 and for the total score between 0.84-0.93/0.76-0.88. Reliability studies demonstrated similar levels of interrater agreement (e.g., r = 0.81 to r = 0.93; e.g.) [START_REF] Brandt | Assessment of psychopathy in a population of incarcerated adolescent offenders[END_REF][START_REF] Forth | Psychopathy and young offenders: prevalence, family background, and violence[END_REF][START_REF] Vincent | Identification of psychopathy in adolescents: The utility of two measures[END_REF]. The internal consistency for the PCL:YV items was high (a = 0.89).

Factor analyses have recently examined the latent dimensions that underlie the pattern of correlations among the PCL:YV item scores (see Table 1). The Hare 4-factor model [START_REF] Hare | The Hare psychopathy checklist-revised, 2nd edn[END_REF][START_REF] Hare | The PCL-R assessment of psychopathy: development, structural properties, and new directions[END_REF][START_REF] Vitacco | Testing of a four-factor model of psychopathy: associations with gender, ethnicity, intelligence and violence[END_REF] proposes that the construct of psychopathy can be best understood in terms of dimensions which reflect interpersonal, affective, lifestyle, and antisocial features. It incorporates all three of the Cooke and Michie factors [START_REF] Cooke | Refining the construct of psychopathy: towards a hierarchical model[END_REF], but at the same time includes a robust antisocial factor. Both the three-and four-factor models have been shown to provide good fit for the PCL-R [START_REF] Hare | The PCL-R assessment of psychopathy: development, structural properties, and new directions[END_REF], and both models also have proven to have good fit values for the PCL:YV for incarcerated boys and girls and for adolescents in the community [START_REF] Forth | The Hare psychopathy checklist: youth version[END_REF][START_REF] Neuman | Factor structure of the Hare psychopathy checklist: youth version (PCL:YV) in incarcerated adolescents[END_REF][START_REF] Salekin | Psychopathy in youth and intelligence: an investigation of Cleckley's hypothesis[END_REF][START_REF] Sevecke | Factor structure of the Hare psychopathy checklist-youth version in female and male detainees and community adolescents[END_REF].

Youth self report (YSR)

The YSR [START_REF] Achenbach | Manual for the youth self-report and profile[END_REF] contains a list of 118 specific problems in children and adolescents, has been standardized on a sample between the ages of 11 and 18 years, and consists of two broadband scales that reflect Ext and Int domains [START_REF] Achenbach | Manual for the youth self-report and profile[END_REF]. The Int composite consists of the anxious/depressed, somatic complaints, and social withdrawal subscales. The Ext composite consists of the aggressive and delinquent behavior subscales. Internal consistency (>0.90), test-retest reliability (0.86-0.90) and factorial validity were found to be satisfying to good [START_REF] Doepfner | Reliability and factorial validity of the YSR and CBCL[END_REF][START_REF] Essau | Reliability and validity of the spence children's anxiety scale and the screen for child anxiety related emotional disorders in German children[END_REF].

Overt aggression scale-modified (OAS-M)

The OAS-M [START_REF] Coccaro | Overt aggression scale-modified. American psychiatric association. Task force for the handbook of psychiatric measures[END_REF] is a psychometric measure to assess the severity, type, and frequency of aggressive behaviour as a clinician-administered, semi-structured interview that was adapted from the Overt Aggression Scale [START_REF] Yudofsky | The overt aggression scale for the objective rating of verbal and physical aggression[END_REF] for use with outpatients. The OAS-M is comprised of an aggression score, which is the sum of four aggression items (verbal assault, assault against objects, assault against self, assault against others), and assesses irritability (sum of two items), and suicidal tendencies (one item). The OAS-M inquires about the last month prior to testing. The validity and reliability of the OAS-M was determined to be statistically significant and high (a = 0.91) [START_REF] Cocarro | Fluoxetine and impulsive aggressive behaviour in personality-disordered subjects[END_REF][START_REF] Coccaro | Overt aggression scale-modified. American psychiatric association. Task force for the handbook of psychiatric measures[END_REF].

Conduct disorder self report (CD-SR)

Symptoms of conduct problems within the last 6 months were assessed by the Self Report Scale for CD from the diagnostic system for mental disorders in childhood and adolescence (DISYPS-KJ) [START_REF] Doepfner | Diagnostik-System fu ¨r Psychische Sto ¨rungen im Kindes-und Jugendalter nach ICD-10 und DSM-IV (DISYPS-KJ)[END_REF]. The scale consists of 25 items which correspond to the 23 symptom criteria for CD in the DSM-IV and the ICD-10. A total score is calculated based on all 25 items, as are scores on two subscales relating to oppositional aggressive behavior (9 items) and antisocial aggressive behavior (16 items). The internal consistency has been reported to be high to very high for the oppositional (a = 0.90) and antisocial (a = 0.71) subscales as well as for the total score (a = 0.89) [START_REF] Doepfner | Diagnostik-System fu ¨r Psychische Sto ¨rungen im Kindes-und Jugendalter nach ICD-10 und DSM-IV (DISYPS-KJ)[END_REF]. In our juvenile sample internal consistencies were as follows: oppositional, a = 0.88; antisocial, a = 0.83; and total score, a = 0.90.

Results j Data analysis

All data were analyzed with SPSS Version 15.0. The variables of the YSR, the CD-SR and the PCL:YV were distributed normally. Means and standard deviations (SD) were computed for all variables of interest; v 2and t tests were used to evaluate differences between female and male groups on demographic variables. For skewed variables (OAS-M) different statistical tests were carried out, such as the non-parametrical U test. To calculate effect sizes (ES), group differences were divided by the pooled estimate of SD. Regarding the hypotheses, we conducted two sets of analyses. To evaluate sex differences, we first compared psychopathology and psychopathy scores in female and male delinquents, using t tests. Furthermore, regression models using a stepwise method were calculated to evaluate the influence of Ext and Int variables on predicting the psychopathy total score and the four factors for delinquent males and females. In step 1, Ext and Int variables were entered in order to examine independent effects on the PCL:YV total score and on each PCL:YV factor. In step 2, only Int variables were entered. The explained amount of variance (R 2 ) is given for each model. Overall significance (a = 0.05) was adjusted for comparisons.

j Psychopathology and psychopathy in delinquent girls and boys

Table 2 displays group differences of psychopathology within the female and male sample. The female sample had significantly higher scores on Int scales (P = 0.001; ES = 0.48), while the males had significantly higher scores on Ext scales (P = 0.034, ES = )0.29, see Table 2). After adjusting for multiple testing, the Anxiousdepressive scale differed significantly between delinquent girls and boys (P < 0.001; ES = 0.45). Boys reported significantly higher scores on the Ext syndrome scale Aggressive behavior (P = 0.034; ES = )0.29), but not with respect to Antisocial behavior (P = 0.091). According to overt aggression (OAS-M) and CD, boys scored higher on the Aggression scale (P < 0.001; d = )0.21), the Irritability scale (P < 0.001; d = )0.70), the Oppositional Aggressive scale (P = 0.001; d = 0.47), on Antisocial Aggressive (P < 0.001; d = -0.71) and on the total score of CD symptoms (P < 0.001; d = )0.67). There was no difference on suicidal behavior (P = 0.381).

Comparing female and male delinquent juveniles on psychopathy, boys scored significantly higher on all four factor scores (P < 0.001) and the PCL:YV total score (P < 0.001). We found the largest effects, with higher scores in boys than girls, regarding psychopathy total score (d = )1.24), the lifestyle (d = )1.17) and the affective factor (d = )1.10).

Regression models: externalizing and internalizing psychopathology predicting psychopathy

Cross-sectional linear regression models explored prediction of the PCL:YV total score and of the four validated dimensions underlying adolescent psychopathy. First, Ext (Externalizing, Antisocial and Aggressive behavior from YSR; Aggression and Irritability from OAS-M; Oppositional-aggressive, Antisocial-aggressive and CD from CD-SR) and Int scales (Anxious-depressive and Internalizing from YSR; Suicidal behavior from OAS-M) were entered into the models. In a second step, only Int scales (Anxious-depressive and Internalizing from YSR; Suicidal behavior from OAS-M) were entered into the model (See Table 3).

j Externalizing and internalizing

Different symptoms of Ext predicted scores on the total factor of psychopathy for boys and girls (see Table 3). Irritability, CD, aggressive behavior, negative anxious-depressive behavior and Int remained significant predictors for the psychopathy total score in boys and accounted for 34% of variance, P < 0.001. Symptoms of anxious-depressive behavior and Int were not a significant predictor of the psychopathy total score for girls. Ext and Aggression (OAS-M), however, were significant predictors for girls, accounting for 46% of the variance, P < 0.001.

Symptoms of Aggressive behavior predicted scores on the interpersonal dimension of psychopathy for boys and girls; however, they accounted for a relatively small proportion of variance (7% for boys, P = 0.05; 7% for girls, P < 0.01). Moreover, antisocial behavior remained a significant predictor of interpersonal symptoms for girls (DR 2 = 3%, P < 0.01). With respect to the affective factor, Irritability, Aggression, negative Anxious-depressive and Int symptoms emerged as significant predictors for boys (R 2 = 33%, P < 0.001). Symptoms of Ext behavior contributed to predicting affective scores only in girls (R 2 = 9%, P < 0.01). In boys, CD and Irritability predicted scores on the lifestyle factor of psychopathy, accounting for 16 and 5% of the variance (P < 0.001). In girls, antisocial behavior and aggression showed an association with the lifestyle factor (45 and 3% of the variance, P < 0.001). Finally, with respect to the antisocial factor, CD and Irritability emerged as significant predictors for boys (R 2 = 41%; R 2 = 8%, P < 0.001). Furthermore, only the contribution of Ext symptoms remained significant for girls (R 2 = 66%, P < 0.001).

j Internalizing Symptoms of Int were not a significant predictor of psychopathy total score for boys (see Table 3). However, suicidal behavior was a significant predictor of psychopathy total score for girls, accounting for 7% of the variance, P < 0.01. With respect to the interpersonal factor, symptoms of Int were not a significant predictor neither for boys nor for girls. In boys, anxious-depressive symptoms emerged as significant negative predictor on the affective factor, accounting for a relative small portion of the variance (7%, P = 0.05). However, Int behavior only predicted scores regarding the affective factor in boys (R 2 = 6%, P < 0.01). In girls, suicidal behavior showed a significant influence on the affective psychopathy factor (R 2 = 3%, P = 0.05). Regarding the lifestyle and the antisocial factor, symptoms of Int were not a significant predictor for boys. In girls, suicidal behavior predicted scores on the lifestyle (R 2 = 5%, P = 0.05) and on the antisocial factor (R 2 = 5%, P = 0.05).

Discussion

The aim of this study was to examine the relationship between psychopathology and psychopathic traits in incarcerated adolescents. By including female and male delinquent juveniles, we addressed gender aspects. Moreover, the present study, the Cologne GAP-Study, was the first to test the applicability of the PCL:YV in a German forensic adolescent sample of both sexes. In accordance with other findings, our results demonstrated gender-based differences regarding the mean Ext psychopathology scores of all measurements used (hypothesis 1). Furthermore, we found differences in the mean scores of the psychopathic dimensions; boys had significantly higher scores on psychopathy, both for total and factor scores. This finding is consistent with past research indicating that males tend to score higher than females on all psychopathic dimensions [START_REF] Essau | Callous-unemotional traits in a community sample of adolescents[END_REF][START_REF] Vitale | Using the psychopathy checklist-revised with female samples: reliability, validity, and implications for clinical utility journal of clinical psychology[END_REF]. Overt aggression defined as physical acts of violence, such as hitting and kicking, was more prevalent among boys, consistent with other investigations [START_REF] Crick | Relational aggression, gender, and socialpsychological adjustment[END_REF][START_REF] Odgers | Aggressive and antisocial girls: research update and challenges[END_REF]. As predicted, the YSR Int profile of incarcerated females compared to males was characterized by a significantly higher Int total score and anxious-depressive behavior. This result is in accordance with earlier investigators' findings, whereupon delinquent girls tended to express more Int, e.g. self-harming behavior [START_REF] Timmons-Mitchell | Comparing the mental health needs of female and male incarcerated juvenile delinquents[END_REF], referring to a development of more Int problem symptoms in girls as compared to more Ext behavior in boys [START_REF] Cauffman | Posttraumatic stress disorder among female juvenile offenders[END_REF].

Regarding hypothesized gender differences (2), we found different relationships between psychopathology and psychopathy in delinquent girls compared to delinquent boys. As predicted, for boys we found a positive relation between Ext and all psychopathy dimensions, at the same time a negative relationship between anxious-depressive behavior and the affective dimension as well as the total score of psychopathy. Dating back to Cleckley's clinical description of the adult psychopath, ''the absence of Ônervousness' or psychoneurotic manifestations'' has often been considered a core characteristic of the psychopathic individual. In Cleckley's account, the absence of anxiety has usually been interpreted as one aspect of a general absence of emotional experience [START_REF] Cleckley | The mask of sanity[END_REF]. Other authors have argued that fearlessness or the absence of behavioral inhibition is a central disposition underlying psychopathy [START_REF] Cloninger | A systematic method for clinical description and classification of personality variants. a proposal[END_REF][START_REF] Fowles | The three arousal model: implications of gray's two-factor learning theory for heart rate, electrodermal activity, and psychopathy[END_REF][START_REF] Lykken | The antisocial personalities[END_REF], a perspective sometimes referred to as the low-fear hypothesis [START_REF] Murrie | Psychopathy screening of incarcerated juveniles: a comparison of measures[END_REF]. Insofar, our results underpin this theory by indicating a negative association between one of the core symptoms of psychopathy (affective) and the total score of the PCL:YV.

In discordance with our hypothesis, we found a positive relation between the YSR subscale Int and the affective dimension as well as the psychopathy total score for the boys. This finding could be explained by the composition of the Int syndrome scale based on physical problems and social withdrawal, phenomena which are associated with psychopathy [START_REF] Forth | The Hare psychopathy checklist: youth version[END_REF].

As for the boys, expectedly, our results confirmed a positive relation between Ext and all psychopathy dimensions among girls. Moreover, we replicated the finding of a positive association between suicidal tendencies and the lifestyle as well as the antisocial psychopathy dimensions for girls and of a negative association with interpersonal features, previously reported in adult incarcerated females [START_REF] Verona | Psychopathy, antisocial personality, and suicide risk[END_REF][START_REF] Verona | Psychopathy and suicidality in female offenders: mediating influences of personality and abuse[END_REF]. This result indicates differing relations between psychopathy and psychopathology in boys than in girls. Cleckley maintained that individuals exhibiting primary traits of psychopathy are characteristically immune to committing suicide, and he included ''suicide rarely carried out'' (p. 359) as one of the key characteristics of primary psychopathy. Other researchers have approached this issue by positing two distinct kinds of antisocial individuals: primary and secondary psychopaths. They [START_REF] Blackburn | An empirical classification of psychopathic personality[END_REF][START_REF] Lynam | Early identification of the fledging psychopath: locating the psychopathic child in the current nomenclature[END_REF][START_REF] Skeem | Two subtypes of psychopathic violent offenders that parallel primary and secondary variants[END_REF] have characterized the primary subtype by low anxiety and antisocial behavior due to a lack of conscience, and the secondary subtype by negative affect and impulsivity due to a neurotic conflict. Our results could be used as indicator that girls may be elaborate to the secondary subtype. Relative to primary, secondary psychopaths manifest more features of psychopathology, including anxiety and mood disorders [START_REF] Vassileva | Psychopathy versus psychopathies in classifying criminal offenders[END_REF], and fewer affective deficits [START_REF] Haapasolo | The psychopathy checklist and non-violent offender groups[END_REF]. Similarly, Newman and his colleagues have often argued that psychopathic individuals characterized by a lack of anxiety or negative affectivity exhibit cognitive deficits and other anomalies that psychopathic individuals with these traits do not [START_REF] Newman | Validating a distinction between primary and secondary psychopathy with measures of Gray's BIS and BAS constructs[END_REF][START_REF] Newman | The impact of motivationally neutral cues on psychopathic individuals: assessing the generality of the response modulation hypothesis[END_REF]. They have theorized that primary and secondary psychopathy may differ in etiology with the former arising from a constitutional or genetic disposition, and the latter as a manifestation of environmental influences (e.g. parental rejection, abuse, poor socialization). Other theorists posited that primary psychopaths have more pronounced traits of emotional detachment linked to the interpersonal and affective features [START_REF] Levenson | Assessing psychopathic attributes in a noninstitutional population[END_REF][START_REF] Mealey | The sociobiology of sociopathy: an integrated evolutionary model[END_REF], secondary psychopaths display more impulsivity, hostility and social deviance [START_REF] Mealey | The sociobiology of sociopathy: an integrated evolutionary model[END_REF], more ''hot headed'' and reactive behavior [START_REF] Karpman | On the need for separating psychopathy into two distinct clinical types: symptomatic and idiopathic[END_REF] linked to the lifestyle and antisocial psychopathy dimensions. The gender difference found in our study-low anxiety in boys and high influence of suicidal behaviour in girls-could indicate that psychopathy in boys corresponds to the primary subtype whereas psychopathy in girls might match with the secondary. Recent cluster analyses of adults have reported that measures of anxiety contribute to differentiation between groups of so-called primary psychopaths and secondary psychopaths [START_REF] Hicks | Identifying psychopathy subtypes on the basis of personality structure[END_REF]61,[START_REF] Swogger | Identifying subtypes of criminal psychopaths: a replication and extension[END_REF][START_REF] Vassileva | Psychopathy versus psychopathies in classifying criminal offenders[END_REF]. Skeem and colleagues found in their sample of 367 adult male prison inmates that secondary psychopaths manifested more borderline personality features, poorer interpersonal functioning (e.g. irritability, withdrawal, poor assertiveness), more symptoms of major mental disorder, greater trait anxiety, and fewer psychopathic traits than primary psychopaths, but levels of antisocial behaviour that were comparable to theirs [START_REF] Skeem | Two subtypes of psychopathic violent offenders that parallel primary and secondary variants[END_REF].

Because the PCL:YV includes criteria such as impulsivity, irresponsibility, and need for stimulation, some researchers have warned that such criteria are almost normative among adolescents, making it difficult to distinguish ''psychopathic traits'' from common adolescent behavior [START_REF] Seagrave | Adolescent development and the measurement of juvenile psychopathy[END_REF]. Same researchers concluded the possibility that behavioral items compartmentalized in the lifestyle and the antisocial factor could artificially inflate psychopathy scores for adolescent girls [START_REF] Odgers | Examining the science and practice of violence risk assessment with female adolescents[END_REF][START_REF] Salekin | Psychopathy and recidivism among female inmates[END_REF]. Moreover, it was interpersonal feature of psychopathy, followed by affective features, which provided greater levels of information than behavioral features for the girls. Further research with girls is needed in order to clarify the specific structure of psychopathy in girls and the differentiation from male psychopathy. In summary, our research suggests some differences in the correlates of the PCL:YV factors for incarcerated boys compared with incarcerated girls. Although adequate reliability and internal consistency for psychopathy in women and girls is proven, boys seem more likely to show core characteristics of psychopathy with regard to the lack of suicidality and a negative relation between anxious-depressive behavior and psychopathy than girls. In accordance with the literature relationships between psychopathic traits and Int disorders (diagnoses, symptoms, and traits) in youth are much less consistent than relationships between psychopathic traits and externalizing disorders.

Future follow-up research is needed that focuses on the issue of comorbid psychopathology and reoffending in female and male adolescents in order to investigate possible gender differences regarding the psychopathy construct and these predictors or protective factors in criminal girls especially. Understanding the etiology of psychopathy, the comorbidity, the patterns of stability and the concomitant neurocognitive impairments separately for boys and girls is not merely of theoretical interest, but will also have treatment and public policy implications. As therapeutic intervention is rare and expensive-especially in prison-targeted treatment for different subtypes of individuals with antisocial behavior will maximise the chances of successful outcome and ensure that scarce resources are allocated most effectively.

j Limitations

There are several limitations to the present study. First, the study was cross-sectional, and findings relied mostly on retrospective reports of suicidality. Second, no information was available regarding the circumstances surrounding participants' suicidal behavior (i.e. desire to die or cry for help). Third, the findings of Int and Ext psychopathology relied on information from self-reports for two of the four measurements (YSR and CD-SR). In addition, due to the incarceration it was not possible to obtain information from parents or teachers. Fourth, the effect of legal involvement cannot be excluded when psychopathology is investigated during incarceration. Fifth, the cross-sectional nature of the study does not permit the drawing of conclusions about any causal linkage between variables or about the stability of these traits.

  (n = 123), M (SD) 11.5 (6.1) 19.3 (9.4) 10.7 (4.5) 12.9 (7.3) 23.5 (10.9) 83.7 (231.8) 4.0 (2.7) 0.5 (1.6) 8.7 (6.8) 9.6 (7.6) 18.3 (13.2) 3.9 (1.89) 3.6 (1.76) 5.5 (2.1) 5.6 (2.64) 1.6 (.62) Boys (n = 91), M (SD) 8.9 (5.4) 15.1 (7.7) 11.6 (3.7) 14.8 (5.9) 26.4 (8.8) 132.1 (234.9) 5.7 (2.0) 0.3 (.8) 11.9 (6.7) 15.4 (8.9) 27.4 (14.0) 5.2 (1.8) 5.4 (1.39) 7.7 (1.48) 7.7 (1.53) 2.4 (.59) T-value, U-value*

24 M

 24 mean, SD standard deviation, ES Effect size, typed in bold: significant differences *U-Value

Table 1 The

 1

			Lifestyle (F3) Antisocial (F4)		Stimulation seeking Poor anger control		Parasitic orientation Early behavior	problems	Lacks goals Juvenile	delinquency	Impulsivity Revocation of	conditional	release	Irresponsibility Criminal versatility
		Hare 4-factor model	Interpersonal (F1) Affective (F2)		Impression Lack of remorse	management	Grandiose sense Shallow affect	of self-worth	Pathological lying Callous/lacking	empathy	Manipulation for Failure to accept	personal gain responsibility
			Impulsive, irresponsible	behavior	Stimulation seeking		Parasitic orientation		Lacks goals		Impulsivity			Irresponsibility
		Cooke and Michie 3-factor model	Arrogant, deceptive Deficient affective	interpersonal experience	Impression Lack of remorse	management	Grandiose sense Shallow affect	of self-worth	Pathological lying Callous/lacking	empathy	Manipulation for Failure to accept	personal gain responsibility
	different factor models	Hare 2-factor model	Interpersonal/ Socially deviant	affective lifestyle	Impression Stimulation seeking	management	Grandiose sense Parasitic orientation	of self-worth	Pathological lying Lacks goals		Manipulation for Impulsivity	personal gain		Lack of remorse Irresponsibility	Shallow affect Poor anger control	Callous/lacking Early behavior	empathy problems	Failure to accept Juvenile delinquency	responsibility	Revocation of	conditional	release

Table 2

 2 YSR scales, OAS-M, CD-SR and PCL:YV for delinquent girls and boys

	PCL:YV
	OAS-M CD-SR	Externalizing Aggression Irritability Suicidal Opp.
		Aggressive	behavior
		Internalizing Antisocial	behavior
	YSR	Anxious-	depressive

Examining relations between psychopathology and psychopathy