Disregard for rules: the early development and predictors of a specific dimension of disruptive behavior disorders.

BACKGROUND: Disregard for rules, an important dimension of oppositional defiant and conduct disorders, is frequent during early childhood, but the development of its chronic form has not been studied during this key socialization period. This study aimed to describe the developmental trajectories of disregard for rules during early childhood and identify prenatal and postnatal predictors for a high trajectory. METHODS: Participants were involved in a longitudinal study of a birth cohort followed yearly from 5 to 74 months of age (N = 1,942). Prenatal and postnatal predictors were measured by parental report at the beginning of the study, and parents reported child disregard for rules at five time points from 29 to 74 months of age. RESULTS: Four groups of children followed distinct and stable trajectories of mother-rated disregard for rules: Very Low (approximately 9.1%), Low (56.9%), Moderate (29.7%) and Chronic (4.3%). As expected, male sex was a significant predictor of the chronic trajectory (OR = 1.76, CI = 1.09-2.83). Mothers' history of antisocial behavior (OR = 1.72, CI = 1.02-2.91), and postnatal depressive symptoms experienced by the mother (OR = 1.71, CI = 1.03-2.84) and the father (OR = 2.02, CI = 1.10-3.71) were also important independent predictors. However, contrary to expectations, children's difficult temperament and parenting at 5 months did not predict chronic disregard for rules beyond other risk factors. CONCLUSIONS: High disregard for rules is fairly stable during early childhood and is associated with risk factors identifiable before and shortly after birth which may be used for targeted prevention.

Depression and anxiety symptoms: onset, developmental course and risk factors during early childhood.

BACKGROUND: Depressive and anxiety disorders are among the top ten leading causes of disabilities. We know little, however, about the onset, developmental course and early risk factors for depressive and anxiety symptoms (DAS). OBJECTIVE: Model the developmental trajectories of DAS during early childhood and to identify risk factors for atypically high DAS. METHOD: Group-based developmental trajectories of DAS conditional on risk factors were estimated from annual maternal ratings (1(1/2) to 5 years) in a large population sample (n = 1759). RESULTS: DAS increased substantially in two of the three distinct trajectory groups identified: High-Rising (14.7%); Moderate-Rising (55.4%); and Low (29.9%). Two factors distinguished the High-Rising group from the other two: Difficult temperament at 5 months (High-Rising vs Moderate-Rising: OR = 1.32; 95% CI = 1.13-1.55; High-Rising vs Low: OR = 1.31, CI = 1.12-1.54) and maternal lifetime major depression (High-Rising vs Moderate-Rising: OR = 1.10; CI = 1.01-1.20; High-Rising vs Low: OR = 1.19; CI = 1.08-1.31). Two factors distinguished the High-Rising group from the Low group: High family dysfunction (OR = 1.24; CI = 1.03-1.5) and Low parental self-efficacy (OR = .71; CI = .54-.94). CONCLUSIONS: DAS tend to increase in frequency over the first 5 years of life. Atypically high level can be predicted from mother and child characteristics present before 6 months of age. Preventive interventions should be experimented with at risk infants and parents.

Maternal prenatal smoking, parental antisocial behavior, and early childhood physical aggression.

This study investigated joint effects of maternal prenatal smoking and parental history of antisocial behavior on physical aggression between ages 17 and 42 months in a population sample of children born in Québec (N = 1,745). An analysis of variance (ANOVA) showed significant main effects of maternal prenatal smoking and a significant interaction between maternal prenatal smoking and mother's history of antisocial behavior in the prediction of children's probability to display high and rising physical aggression. The interaction indicated that the effects of heavy smoking during pregnancy (> or =10 cigarettes/day) were greater when the mother also had a serious history of antisocial behavior. The effects remained significant after the introduction of control variables (e.g., hostile-reactive parenting, family functioning, parental separation/divorce, family income, and maternal education). Another significant interaction not accounted for by control variables was observed for maternal prenatal smoking and family income, indicating more serious effects of maternal prenatal smoking under relatively low-income, conditions. Both interactions indicate critical adversities that, in combination with maternal prenatal smoking, have supra-additive effects on (the development of) physical aggression during early childhood. These findings may have implications for the selection of intervention targets and strategies.

Controlling parenting and physical aggression during elementary school.

The goal of the present study was to examine whether controlling parenting contributes to the problem of physical aggression. Developmental trajectories of children's physical aggression were modeled from yearly teachers' ratings, from ages 6 to 12. Multinomial logistic regressions (N = 1,508) served to identify risk factors that distinguish children who display different levels of physical aggression throughout grade school. Results revealed that being a boy and having a reactive temperament were important child predictors. Parental separation and an early onset of motherhood were also significant risk factors. Finally, mothers' controlling parenting increased the odds of following the highest trajectory of physical aggression, above and beyond the previous risk factors.

Girls' hyperactivity and physical aggression during childhood and adjustment problems in early adulthood: a 15-year longitudinal study.

CONTEXT: The co-occurrence of hyperactivity and conduct problems in childhood seems to increase the risk of early adulthood adjustment problems in males. However, little is known about this topic in females. OBJECTIVES: To describe the joint developmental trajectories of female hyperactivity and physical aggression during childhood and to examine the extent to which high trajectories of hyperactivity and physical aggression predict adjustment problems in early adulthood. DESIGN, SETTING, AND PARTICIPANTS: A total of 881 females from a population-based sample were studied. Developmental trajectories were described using teachers' ratings of behavior problems from the age of 6 to 12 years. MAIN OUTCOME MEASURES: Age 21 years self-reports of substance use problems, criminal behaviors, aggression in intimate relationships, early pregnancy, educational attainment, and welfare assistance. RESULTS: Between the ages of 6 and 12 years, the frequency of hyperactivity and physical aggression tended to decrease for most girls. Those on a trajectory of high hyperactivity (HH) and high physical aggression (HPA) and a trajectory of HH alone were significantly more likely to report nicotine use problems (odds ratio [OR], 2.16 [95% confidence interval {CI}, 1.30-3.56] and OR, 2.23 [95% CI, 1.39-3.58], respectively), mutual psychological aggression in intimate relationships (OR, 2.28 [95% CI, 1.24-4.18] and OR, 2.14 [95% CI, 1.19-3.85], respectively), and low educational attainment (OR, 4.09 [95% CI, 2.33-7.18] and OR, 3.21 [95% CI, 1.84-5.59], respectively) compared with the other females at the age of 21 years. Only the HH-HPA females were significantly more likely to report physical aggression (OR, 2.48 [95% CI, 1.41-4.37]) and psychological aggression (OR, 2.54 [95% CI, 1.48-4.36]) in intimate relationships, early pregnancy (OR, 2.31 [95% CI, 1.17-4.56]), and welfare assistance (OR, 2.68 [95% CI, 1.33-5.41]) compared with the other females. CONCLUSIONS: Elementary school girls with elevated levels of hyperactivity should be targeted for intensive prevention programs. These interventions should take into account the presence or absence of HPA.

The role of maternal education and nonmaternal care services in the prevention of children's physical aggression problems.

CONTEXT: Physical violence is an important health problem, and low maternal education is a significant risk for the development of chronic physical aggression (PA). We hypothesized that nonmaternal care (NMC) services could prevent the development of childhood PA problems, depending on the age at which the services are initiated. Method Children who followed a trajectory of atypically frequent PA between 17 and 60 months of age among a population sample of 1691 Canadian families were identified. Maternal education and NMC were considered in predicting group membership while controlling for confounding family characteristics. RESULTS: Children of mothers with low education levels (ie, no high school diploma) were less likely to receive NMC. Those who did receive such care had significantly lower risk of a high PA trajectory. Results from logistic regressions indicated that NMC reduced the risk of high PA, especially when initiated before age 9 months (odds ratio, 0.20; 95% confidence interval, 0.05-0.90). Children of mothers who graduated from high school were less at risk of PA problems, and NMC had no additional protective effect. CONCLUSIONS: Nonmaternal care services to children of mothers with low levels of education could substantially reduce their risk of chronic PA, especially if provided soon after birth. Because children most likely to benefit from NMC services are less likely to receive them, special measures encouraging the use of NMC services among high-risk families are needed.

Natural history of suicidal behaviors in a population-based sample of young adults.

BACKGROUND: Suicidal behaviors in young individuals represent an important public health problem. Understanding their natural history and relationships would therefore be of clinical and research value. In this study, we examined the natural histories of several suicidal behaviors and investigated two conceptual models of suicidality (dimensional and categorical) in the context of adolescent and adult-onset suicide attempts. METHOD: Participants were members of a prospectively studied, representative, population-based school cohort followed since age 6 (n = 3017) through mid-adolescence (n = 1715) to their early twenties (n = 1684). Outcome measures included suicidal ideation, attempts and completions. RESULTS: Approximately one in 500 individuals died by suicide. About 33% had suicidal ideas and 9.3% made at least one suicide attempt. Over half (4.9%) of the self-reported attempters made their first attempt before age 18. With the exception of current suicidal ideas, non-fatal suicidal behaviors were more prevalent in females. In general, parental and cross-sectional self-reports underestimated suicidality rates. Aikaike (AIC) and Bayesian (BIC) information criteria suggested the ordinal model, and dimensional conceptualization of suicide attempts of different onset age, to be more optimal than its multinomial/categorical counterpart (ordinal: AIC 567.55, BIC 635.67; multinomial: AIC 616.59, BIC 723.83). Both models, nevertheless, identified five common factors of relevance to suicidal diathesis: gender, disruptive disorders, childhood anxiousness and abuse, and suicidal thoughts. CONCLUSIONS: Non-fatal suicidal behaviors in adolescents and young adults are more common than suggested by cross-sectional studies and parental reports. The dimensional model may be more useful in explaining the relationship of suicide attempts of different age of onset.

The association of major depression, conduct disorder, and maternal overcontrol with a failure to show a cortisol buffered response in 4-month-old infants of teenage mothers.

BACKGROUND: Adolescent pregnancy can be associated with major depression (MD) and conduct disorder (CD). Some infants of adolescent mothers are prenatally exposed to these factors, which may result in heightened risk for perturbations of their stress systems. Between 2 and 4 months, a normal shift occurs in the adrenocortical system in which we observe a marked decrease in infant cortisol response when facing mild stressors. This study aimed to explore whether MD (lifetime, during pregnancy, postpartum), CD, and maternal overcontrol are associated with increased cortisol reactivity in 4-month-old infants of teenage mothers. METHODS: Using arm restraint as a stressor, morning salivary cortisol was taken prestressor and poststressor in 212 infants during a laboratory visit. Major depression and CD were measured with the computerized National Institute of Mental Health Diagnostic Interview Schedule (NIMH-DIS), postpartum depressive mood was measured with the Edinburgh Postnatal Depression Scale, and overcontrol was observed with the CARE-Index. RESULTS: Independent of the predictors, there was a dampened cortisol response. Infants of mothers with lifetime MD and of average to highly overcontrolling mothers showed increased cortisol reactivity. Conduct disorder and cortisol levels were not associated. CONCLUSIONS: Future studies should detect whether the absence of a dampened cortisol response in infants whose mothers have lifetime MD or display overcontrolling parenting is stable over time.

Associations of maternal prenatal smoking with early childhood physical aggression, hyperactivity-impulsivity, and their co-occurrence.

This study investigated associations between maternal prenatal smoking and physical aggression (PA), hyperactivity-impulsivity (HI) and co-occurring PA and HI between ages 17 and 42 months in a population sample of children born in Québec (Canada) in 1997/1998 (N=1745). Trajectory model estimation showed three distinct developmental patterns for PA and four for HI. Multinomial regression analyses showed that prenatal smoking significantly predicted children's likelihood to follow different PA trajectories beyond the effects of other perinatal factors, parental psychopathology, family functioning and parenting, and socio-economic factors. However, prenatal smoking was not a significant predictor of HI in a model with the same control variables. Further multinomial regression analyses showed that, together with gender, presence of siblings and maternal hostile reactive parenting, prenatal smoking independently predicted co-occurring high PA and high HI compared to low levels of both behaviors, to high PA alone, and to high HI alone. These results show that maternal prenatal smoking predicts multiple behavior regulation problems in early childhood.

Gender differences in physical aggression: A prospective population-based survey of children before and after 2 years of age.

There has been much controversy over the past decades on the origins of gender differences in children's aggressive behavior. A widely held view is that gender differences emerge sometime after 2 years of age and increase in magnitude thereafter because of gender-differentiated socialization practices. The objective of this study was to test for (a) gender differences in the prevalence of physical aggression in the general population of 17-month-old children and (b) change in the magnitude of these differences between 17 and 29 months of age. Contrary to the differential socialization hypothesis, the results showed substantial gender differences in the prevalence of physical aggression at 17 months of age, with 5% of boys but only 1% of girls manifesting physically aggressive behaviors on a frequent basis. The results suggest that there is no change in the magnitude of these differences between 17 and 29 months of age.

[Prevalence and co-occurrence of five types of ill-treatment in relation with depression and conduct disorder in adolescent mothers]. / Prévalence et cooccurrence de cinq formes de maltraitance en lien avec la dépression et le trouble de la conduite chez les mères adolescentes.

In this article, the authors reflect on co-occurrence of different types of maltreatment that adolescent mothers have suffered during their childhood in order to better understand intergenerational transmission of maltreatment. They underline that studies on maltreatment that adults or adolescents have been subjected to during their childhood generally do not take into account co-occurrence of different types of maltreatment. The authors first attempt to verify if adolescent mothers are different from women of the general population in regards to prevalence and co-occurrence of various types of maltreatment suffered during their own development. They then try to establish prevalence and co-occurrence of types of maltreatment in relation to diagnoses of major depression or conduct disorder in adolescent mothers.

The evolution of problem and social competence behaviors during toddlerhood: A prospective population-based cohort survey.

Research in developmental psychopathology has long been preoccupied with rather broad categories of behavior, but we know little about the specific behaviors that comprise these categories. The objective of this study was to: (a) estimate the prevalence of problem and social competence behaviors in the general population of children at 17 months of age, and (b) describe the continuity and discontinuity in the degree to which children exhibit these behaviors between 17 and 29 months of age. The results show that frequent problem behaviors are not typical of children under two years of age. Further, the results suggest that it is possible to distinguish between different types of problem behaviors before two years of age. In addition, the results show that gender differences in some problem behaviors are already present before two years of age, and increase in magnitude during toddlerhood. Finally, the results show that interindividual differences in problem behaviors observed before two years of age are stable. The predictive accuracy of frequent problem behaviors in children at 17 months of age was limited, however, with often a majority of toddlers not behaving this way a year later. Overall, our results suggest that toddlerhood represents a critical period when behavioral and emotional problems of potentially clinical significance emerge. Pediatricians should routinely ask parents to report the frequency of their young children's problem behaviors during child health supervision visits so that children whose frequent problem behaviors persist over time can be identified and possibly referred for treatment.

Histories of child maltreatment and psychiatric disorder in pregnant adolescents.

OBJECTIVE: The study investigated histories of child maltreatment and psychiatric disorder in a high-risk sample of pregnant adolescents. METHOD: Cross-sectional data were obtained for 252 pregnant adolescents from high school, hospital, and group home settings in Montreal (Canada). Adolescents completed a child maltreatment questionnaire and a psychiatric interview on lifetime conduct and major depressive disorders. Latent class analysis was used to model the association between child maltreatment and psychiatric disorder. RESULTS: Analyses indicated two latent classes: pregnant adolescents with no reported child maltreatment history (79%) and those with multiple forms of maltreatment (21%). There was no association between the child maltreatment latent variable and major depressive disorder. Rather, depression was related specifically to one form of maltreatment (i.e., sexual abuse, odds ratio = 2.60). Depression also showed a significant relationship with conduct disorder (odds ratio = 3.70). Pregnant adolescents with multiple forms of child maltreatment had a fourfold risk of also having conduct disorder, compared with nonmaltreated adolescents. CONCLUSIONS: In this sample of pregnant adolescents, prior experience of multiple forms of child maltreatment was prevalent, as were depression and conduct disorder. Clinicians need to screen for histories of child maltreatment and psychiatric disorder and to introduce effective interventions for pregnant adolescents and their children.

Personality traits as correlates of suicide attempts and suicidal ideation in young adults.

BACKGROUND: Adults in their twenties appear to be at high risk for suicidal behaviors (SBs) and there is substantial evidence suggesting that certain personality traits may increase individual vulnerability to suicide. METHOD: We investigated relationships of personality traits with two SBs in a cohort (n=1140) of 21- to 24-year-old adults, representative of the general population of Quebec. Subjects were assessed using a series of structured diagnostic and personality trait questionnaires. Multivariate logistic regression analyses were employed to identify personality trait correlates of suicide-attempt history and serious suicidal ideation in the context of other known risk factors, such as psychopathology and experiences of childhood sexual and physical abuse. RESULTS: Traits of conduct problems contributed to both suicide attempts [odds ratio (OR) 1.03, 95% confidence interval (CI) 1.01-1.06] and suicidal ideation (OR 1.04, 95% CI 1.02-1.07), while identity problems (OR 1.10, 95% CI 1.07-1.13) and gender-moderated impulsivity contributed exclusively to suicidal ideation. CONCLUSIONS: Personality traits may make independent contributions to current suicidal ideation and previous suicide attempts in certain subgroups of suicidal individuals. In order to further explore their utility as markers of suicide risk and targets of intervention further investigation in clinical samples and other cultural and age groups is necessary.

Sex and informant effects on diagnostic comorbidity in an adolescent community sample.

OBJECTIVE: To investigate sex and informant effects on comorbidity rates for anxiety disorders, depressive disorders, attention-deficit hyperactivity disorder (ADHD), and conduct-oppositional disorder (CD-ODD) in an adolescent community sample. METHOD: The Diagnostic Interview Schedule for Children-2.25 (DISC-2.25) was administered to 1201 adolescents and their mothers. RESULTS: The highest comorbidity risk found was between ADHD and CD-ODD, with odds ratios (ORs) of 17.6 for adolescent reports and 12.0 for mother reports. The second-highest comorbidity risk, with ORs of 13.2 for adolescent reports and 11.0 for mother reports, was between anxiety and depressive disorders. There was not much overlap between internalizing and externalizing disorders. Adolescent girls had higher rates of coexisting anxiety and depressive disorders, whereas adolescent boys had higher rates of coexisting ADHD and CD-ODD. There was partial support for the hypothesis that adolescent-reported comorbidity rates would exceed mother-reported rates. CONCLUSIONS: There is a greater cooccurrence of within-category, compared with between-category, disorders. Adolescent girls are more likely to have coexisting internalizing disorders, while adolescent boys are more likely to have coexisting externalizing disorders. Mothers tend to report more externalizing disorders (that is, ADHD), while adolescents generally report more internalizing disorders.

The genetic-environmental etiology of parents' perceptions and self-assessed behaviours toward their 5-month-old infants in a large twin and singleton sample.

BACKGROUND: Given the importance of parenting for the child's early socio-emotional development, parenting perceptions and behaviours, and their correlates, should be assessed as early as possible in the child's life. The goals of the present study were 1) to confirm, in two parallel population-based samples, including a large sample of twins, the factor structure of a new self-administered questionnaire assessing both parents' specific parenting perceptions and behaviours toward their 5-month-old infants (i.e., parental self-efficacy, perceived parental impact, parental hostile-reactive behaviours and parental overprotection), 2) to identify the specific risk factors associated with the negative side of these parenting dimensions, 3) to document the genetic-environmental etiology of these parenting dimensions through the twin method. METHODS: Parents (2,122 mothers and 1,829 fathers) of 5-month-old infants, and parents of 5-month-old infant twins (510 families) completed the questionnaire (28 items). The data were submitted to a series of confirmatory factor analyses. The contribution to parenting of a variety of risk factors was examined in the two samples using regression analyses. A series of quantitative genetic analyses were performed to quantify the different sources of variation in parenting. RESULTS: A consistent factor structure was found across informants and across samples. There were significant mean differences in parenting between mothers and fathers, as well as between parents of twins and parents of singletons. A differentiated pattern of association with risk factors was found for each dimension of parenting. The twin analyses revealed that shared environment accounted for each parenting dimension. Maternal hostile-reactive behaviours were also moderately related to genetic factors in the child and this association was mainly mediated by the infant difficultness. CONCLUSIONS: The overall pattern of results was consistent with Belsky's (1984) view of parenting as multiply determined. The longitudinal follow-up of these families should provide the means for testing developmental models about the determinants and outcomes of these parenting dimensions.

Individual change in methylphenidate use in a national sample of children aged 2 to 11 years.

OBJECTIVES: To determine methylphenidate use in children aged 2 to 13 years. To provide age- and sex-specific estimates of methylphenidate initiation and cessation during a 2-year period. METHOD: Data from 2 cycles of a Canadian household survey yielded a sample of over 10 000 children aged 2 to 11 years at Cycle 1 who continued to participate at Cycle 2. We used logit modelling to estimate Cycle 2 methylphenidate use, methylphenidate use over a 2-year period, and methylphenidate initiation and cessation from Cycles 1 to 2. RESULTS: In 1996 and 1997, methylphenidate use ranged from 0.32% to 6.31% among children aged 4 to 13 years. School-aged boys were more likely than girls to use methylphenidate. Odds were greater for boys aged 6 to 7 years than for boys aged 4 to 5 years; they were also greater for boys aged 10 to 11 years than for boys aged 12 to 13 years. Almost 1% of children used methylphenidate at both data cycles. Odds of Cycle 2 methylphenidate use were 135 times greater for children using methylphenidate at Cycle 1, compared with nonusers. Methylphenidate initiation ranged from 0.20% to 3.34%, and school-aged boys had higher initiation rates than girls. Cessation rates ranged from 18% to78%, and there were no statistically significant differences by age and sex. CONCLUSIONS: Methylphenidate prevalence findings are consistent with past studies. We found an age-by-sex interaction on methylphenidate use. We also found both continuity and discontinuity in methylphenidate use.

Physical aggression during early childhood: trajectories and predictors.

INTRODUCTION: This study aimed to identify the trajectories of physical aggression during early childhood and antecedents of high levels of physical aggression early in life. METHODS: 572 families with a 5-month-old newborn were recruited. Assessments of physical aggression frequency were obtained from mothers at 17, 30, and 42 months after birth. Using a semiparametric mixture model and multivariate logit regression analyses, distinct clusters of physical aggression trajectories were identified, as well as family and child characteristics that predict high level aggression trajectories. RESULTS: THREE TRAJECTORIES OF PHYSICAL AGGRESSION WERE IDENTIFIED: 1. children (28% of sample) who displayed little or no physical aggression, 2. approximately 58% followed a rising trajectory of modest aggression, and 3. a rising trajectory of high physical aggression (14%). CONCLUSIONS: Children who are at highest risk of not learning to regulate physical aggression in early childhood have mothers with a history of antisocial behaviour during their school years, mothers who start childbearing early and who smoke during pregnancy, and parents who have low income and have serious problems living together. Preventive interventions should target families with high-risk profiles on these variables.

Construct validity of an instrument to assess major depression in parents in epidemiologic studies.

OBJECTIVE: The Longitudinal Study of Child Development in Quebec (LSCDQ) is a community study of children that examines the risk factors, such as parental depression, linked to childhood psychopathology and maladaptive functioning. Our goal was to test the construct validity of an instrument to assess major depression in the parents. METHOD: Parents of a representative sample of 2120 infants born in the province of Quebec in 1998 were selected. The major depression instrument was administered to the parents when the infants were aged 29 months. We tested the construct validity of the instrument by examining 1) sex differences in symptoms and prevalence, 2) the rank order of the prevalence of symptoms, 3) the clustering of symptoms, and 4) the association of depression with functional impairment and treatment-seeking behaviour. RESULTS: Depression was twice as common in mothers as in fathers. Most mothers and fathers who reported ever being depressed for 2 or more weeks had also experienced at least 4 additional depression symptoms. The rank order of symptom prevalence was comparable to that found in other studies. At least 50% of parents reported having talked to a professional and that suffering from depression had interfered with their functioning. CONCLUSIONS: The expected sex differences, the rank order of symptom prevalence, the symptom clustering, and the associations with functional impairment and treatment-seeking behaviour support the construct validity of a brief questionnaire on parental major depression.

A new look at inter-informant agreement on conduct disorder using a latent class approach.

This study examined agreement on aggressive and nonaggressive conduct disorder in a general population sample of 14- to 17-year-old adolescents (n=1165) and their mothers. We collected diagnostic interview data and applied latent class analyses to estimate inter-informant agreement. The preferred model for aggressive conduct disorder for both males and females was a one-latent-variable/two-class model specifying no inter-informant disagreement beyond chance expectations. This model estimated the prevalence of aggressive conduct disorder to be 13% for males and 0.4% for females. For nonaggressive conduct disorder, a one-latent-variable/three-class model specifying asymmetric agreement was preferred for both males and females. This model estimated the prevalence of nonaggressive conduct disorder in adolescents to be 18% according to males and 13% according to mothers. Prevalence estimates were 12% according to females and 7% according to mothers. Symptom sensitivity estimates for all models were poor whereas specificity estimates were near perfect to perfect. Males had higher rates of aggressive and nonaggressive conduct disorder across informants. There was a high level of adolescent-mother agreement on both types of conduct disorder. However, there were some differences, suggesting that aggressive and nonaggressive are two valid subtypes of conduct disorder with different prevalence estimates and agreement levels.