The CODATwins Project: The Current Status and Recent Findings of COllaborative Project of Development of Anthropometrical Measures in Twins.

The COllaborative project of Development of Anthropometrical measures in Twins (CODATwins) project is a large international collaborative effort to analyze individual-level phenotype data from twins in multiple cohorts from different environments. The main objective is to study factors that modify genetic and environmental variation of height, body mass index (BMI, kg/m2) and size at birth, and additionally to address other research questions such as long-term consequences of birth size. The project started in 2013 and is open to all twin projects in the world having height and weight measures on twins with information on zygosity. Thus far, 54 twin projects from 24 countries have provided individual-level data. The CODATwins database includes 489,981 twin individuals (228,635 complete twin pairs). Since many twin cohorts have collected longitudinal data, there is a total of 1,049,785 height and weight observations. For many cohorts, we also have information on birth weight and length, own smoking behavior and own or parental education. We found that the heritability estimates of height and BMI systematically changed from infancy to old age. Remarkably, only minor differences in the heritability estimates were found across cultural-geographic regions, measurement time and birth cohort for height and BMI. In addition to genetic epidemiological studies, we looked at associations of height and BMI with education, birth weight and smoking status. Within-family analyses examined differences within same-sex and opposite-sex dizygotic twins in birth size and later development. The CODATwins project demonstrates the feasibility and value of international collaboration to address gene-by-exposure interactions that require large sample sizes and address the effects of different exposures across time, geographical regions and socioeconomic status.

Environmental influence of problematic social relationships on adolescents' daily cortisol secretion: a monozygotic twin-difference study.

BACKGROUND: This study investigated the potential environmental effects of peer victimization and the quality of relationships with parents and friends on diurnal cortisol secretion in mid-adolescence. METHOD: This study used the monozygotic (MZ) twin-difference design to control for genetic effects and thus estimate the unique environmental influences on diurnal cortisol. Participants were 136 MZ twin pairs (74 female pairs) for whom cortisol was assessed four times per day over four collection days grouped in a 2-week period in grade 8 (mean age = 14.07 years). Participants also provided self-reports of peer victimization from grade 4 to grade 8 and of the relationship quality with the mother, father and best friend in grade 8. RESULTS: The expected pattern of diurnal cortisol secretion was observed, with high levels at awakening followed by an increase 30 min later and a progressive decrease subsequently. Controlling for a host of confounders, only within-twin pair differences in peer victimization and a problematic relationship with the mother were significantly linked to twin differences in diurnal cortisol secretion. Specifically, whereas a more problematic mother-child relationship was associated with morning cortisol secretion, peer victimization was linked to cortisol secretion later in the day (diurnal slope). CONCLUSIONS: Controlling for genetic influences and other confounders, stressful relationships with peers and the mother exert unique and time-specific environmental influences on the pattern of diurnal cortisol secretion in mid-adolescence.

Monoamine oxidase A gene promoter methylation and transcriptional downregulation in an offender population with antisocial personality disorder.

BACKGROUND: Antisocial personality disorder (ASPD) is characterised by elevated impulsive aggression and increased risk for criminal behaviour and incarceration. Deficient activity of the monoamine oxidase A (MAOA) gene is suggested to contribute to serotonergic system dysregulation strongly associated with impulsive aggression and antisocial criminality. AIMS: To elucidate the role of epigenetic processes in altered MAOA expression and serotonin regulation in a population of incarcerated offenders with ASPD compared with a healthy non-incarcerated control population. METHOD: Participants were 86 incarcerated participants with ASPD and 73 healthy controls. MAOA promoter methylation was compared between case and control groups. We explored the functional impact of MAOA promoter methylation on gene expression in vitro and blood 5-HT levels in a subset of the case group. RESULTS: Results suggest that MAOA promoter hypermethylation is associated with ASPD and may contribute to downregulation of MAOA gene expression, as indicated by functional assays in vitro, and regression analysis with whole-blood serotonin levels in offenders with ASPD. CONCLUSIONS: These results are consistent with prior literature suggesting MAOA and serotonergic dysregulation in antisocial populations. Our results offer the first evidence suggesting epigenetic mechanisms may contribute to MAOA dysregulation in antisocial offenders.

A longitudinal twin study of physical aggression during early childhood: evidence for a developmentally dynamic genome.

BACKGROUND: Physical aggression (PA) tends to have its onset in infancy and to increase rapidly in frequency. Very little is known about the genetic and environmental etiology of PA development during early childhood. We investigated the temporal pattern of genetic and environmental etiology of PA during this crucial developmental period. METHOD: Participants were 667 twin pairs, including 254 monozygotic and 413 dizygotic pairs, from the ongoing longitudinal Quebec Newborn Twin Study. Maternal reports of PA were obtained from three waves of data at 20, 32 and 50 months. These reports were analysed using a biometric Cholesky decomposition and linear latent growth curve model. RESULTS: The best-fitting Cholesky model revealed developmentally dynamic effects, mostly genetic attenuation and innovation. The contribution of genetic factors at 20 months substantially decreased over time, while new genetic effects appeared later on. The linear latent growth curve model revealed a significant moderate increase in PA from 20 to 50 months. Two separate sets of uncorrelated genetic factors accounted for the variation in initial level and growth rate. Non-shared and shared environments had no effect on the stability, initial status and growth rate in PA. CONCLUSIONS: Genetic factors underlie PA frequency and stability during early childhood; they are also responsible for initial status and growth rate in PA. The contribution of shared environment is modest, and perhaps limited, as it appears only at 50 months. Future research should investigate the complex nature of these dynamic genetic factors through genetic-environment correlation (r GE) and interaction (G×E) analyses.

Childhood trajectories of inattention, hyperactivity and oppositional behaviors and prediction of substance abuse/dependence: a 15-year longitudinal population-based study.

Numerous prospective studies have shown that children diagnosed with attention deficit/hyperactivity disorder (ADHD) are at higher risk of long-term substance abuse/dependence. However, there are three important limits to these studies: (a) most did not differentiate the role of hyperactivity and inattention; (b) most did not control for associated behavioral problems; and (c) most did not consider females. Our aim was to clarify the unique and interactive contributions of childhood inattention and hyperactivity symptoms to early adulthood substance abuse/dependence. Behavioral problems of 1803 participants (814 males) in a population-based longitudinal study were assessed yearly between 6 and 12 years by mothers and teachers. The prevalence of substance abuse/dependence at age 21 years was 30.7% for nicotine, 13.4% for alcohol, 9.1% for cannabis and 2.0% for cocaine. The significant predictors of nicotine dependence were inattention (odds ratio (OR): 2.25; 95% confidence interval (CI): 1.63-3.11) and opposition (OR: 1.65; 95%: 1.20-2.28). Only opposition contributed to the prediction of cannabis dependence (OR: 2.33; 95% CI: 1.40-3.87) and cocaine dependence (OR: 2.97; 95% CI: 1.06-8.57). The best behavioral predictor of alcohol abuse/dependence (opposition) was only marginally significant (OR: 1.38; 95% CI: 0.98-1.95). Frequent oppositional behaviors during elementary school were clearly the most pervasive predictors of substance abuse/dependence in early adulthood. The association of childhood ADHD with substance abuse/dependence is largely attributable to its association with opposition problems during childhood. However, inattention remained an important predictor of nicotine dependence, in line with genetic and molecular commonalities between the two phenotypes suggested in the literature.

Childhood trajectories of anxiousness and disruptiveness explain the association between early-life adversity and attempted suicide.

BACKGROUND: Suicidal behavior is frequently associated with a history of childhood abuse yet it remains unclear precisely how early life adversity may increase suicide risk later in life. As such, our aim was to examine whether lifetime trajectories of disruptiveness and anxiousness trait dysregulation explain the association between childhood adversity and suicidal behavior; and moreover, to test the potential modifying effects of mental disorders on these associations. METHOD: A sample of 1776 individuals from a prospective school-based cohort followed longitudinally for over 22 years was investigated. We tested the influence of disruptiveness and anxiousness trajectories from age 6 to 12 years on the association between childhood adversity (i.e. sexual and physical abuse) and history of suicide attempts (SA) using logistic regression models. Both adolescent externalizing and internalizing Axis I disorders and gender were tested as potential modifiers of these associations. RESULTS: Four distinct longitudinal trajectories were identified for both disruptiveness and anxiousness. The high disruptiveness trajectory accounted for the association between childhood adversity and SA, but only for females. The high anxiousness trajectory also explained the association between adversity and SA; however, in this case it was not sex but mental disorders that influenced the potency of the mediating effect. More specifically, anxiousness fully explained the effect of adversity on SA in the presence of externalizing disorders, whereas in the absence of these disorders, this effect was significantly attenuated. CONCLUSIONS: This study provides evidence that both disruptiveness and anxiousness play an important role in explaining the relationship between childhood adversity and SA.

Differences and similarities in the serotonergic diathesis for suicide attempts and mood disorders: a 22-year longitudinal gene-environment study.

To investigate similarities and differences in the serotonergic diathesis for mood disorders and suicide attempts, we conducted a study in a cohort followed longitudinally for 22 years. A total of 1255 members of this cohort, which is representative of the French-speaking population of Quebec, were investigated. Main outcome measures included (1) mood disorders (bipolar disorder and major depression) and suicide attempts by early adulthood; (2) odds ratios and probabilities associated with 143 single nucleotide polymorphisms in 11 serotonergic genes, acting directly or as moderators in gene-environment interactions with childhood sexual or childhood physical abuse (CPA), and in gene-gene interactions; (3) regression coefficients for putative endophenotypes for mood disorders (childhood anxiousness) and suicide attempts (childhood disruptiveness). Five genes showed significant adjusted effects (HTR2A, TPH1, HTR5A, SLC6A4 and HTR1A). Of these, HTR2A variation influenced both suicide attempts and mood disorders, although through different mechanisms. In suicide attempts, HTR2A variants (rs6561333, rs7997012 and rs1885884) were involved through interactions with histories of sexual and physical abuse whereas in mood disorders through one main effect (rs9316235). In terms of phenotype-specific contributions, TPH1 variation (rs10488683) was relevant only in the diathesis for suicide attempts. Three genes contributed exclusively to mood disorders, one through a main effect (HTR5A (rs1657268)) and two through gene-environment interactions with CPA (HTR1A (rs878567) and SLC6A4 (rs3794808)). Childhood anxiousness did not mediate the effects of HTR2A and HTR5A on mood disorders, nor did childhood disruptiveness mediate the effects of TPH1 on suicide attempts. Of the serotonergic genes implicated in mood disorders and suicidal behaviors, four exhibited phenotype-specific effects, suggesting that despite their high concordance and common genetic determinants, suicide attempts and mood disorders may also have partially independent etiological pathways. To identify where these pathways diverge, we need to understand the differential, phenotype-specific gene-environment interactions such as the ones observed in the present study, using suitably powered samples.

Associations among oxytocin receptor gene (OXTR) DNA methylation in adulthood, exposure to early life adversity, and childhood trajectories of anxiousness.

Recent models propose deoxyribonucleic acid methylation of key neuro-regulatory genes as a molecular mechanism underlying the increased risk of mental disorder associated with early life adversity (ELA). The goal of this study was to examine the association of ELA with oxytocin receptor gene (OXTR) methylation among young adults. Drawing from a 21-year longitudinal cohort, we compared adulthood OXTR methylation frequency of 46 adults (23 males and 23 females) selected for high or low ELA exposure based on childhood socioeconomic status and exposure to physical and sexual abuse during childhood and adolescence. Associations between OXTR methylation and teacher-rated childhood trajectories of anxiousness were also assessed. ELA exposure was associated with one significant CpG site in the first intron among females, but not among males. Similarly, childhood trajectories of anxiousness were related to one significant CpG site within the promoter region among females, but not among males. This study suggests that females might be more sensitive to the impact of ELA on OXTR methylation than males.

Predicting early onset of male antisocial behavior from preschool behavior.

METHODS: Data from a large longitudinal study of boys who were between kindergarten and age 13 years were used to (1) test whether Gray's and Cloninger's personality dimensions measured in kindergarten predicted the early onset of stable, highly delinquent behavior; (2) test whether 1, 2, or 3 dimensions were needed; and (3) test the predictive value of a categorical approach. RESULTS: The impulsivity dimension was the best predictor of the early onset of stable, highly delinquent behavior. Anxiety and reward dependence made significant but weaker contributions. The categorical approach corroborated Cloninger's suggestion that boys who are high in impulsivity, low in anxiety, and low in reward dependence would be more at risk for delinquent involvement. Boys who were high in impulsivity and low in anxiety but high in reward dependence were much less at risk for delinquency. Differences in antisocial behavior among extreme kindergarten personality groups were stable from ages 11 to 13 years. CONCLUSIONS: The behavioral activating system appears to be the major dimension underlying the propensity toward early onset of antisocial behavior, but both the behavioral inhibition system and the need for social rewards play important roles. The behavioral style (personality) that results from the interplay of these systems is clearly in place by the kindergarten year. Preventive efforts should target preschool children with at-risk behavior profiles. However, longitudinal-experimental studies with at least yearly assessments between birth and school-entry age are needed to understand the extent to which the behavioral styles are antecedent to preschool disruptive behavior disorders.

Boys' behavioral inhibition and the risk of later delinquency.

BACKGROUND: In some studies, shyness and anxiety have protected at-risk boys from developing delinquency. In others, shyness and withdrawal have increased risk. We argue that this is because behavioral inhibition, which is the protective factor, has been confounded with social withdrawal and other constructs. Our study addresses 3 major questions: (1) is behavioral inhibition, as distinguished from social withdrawal, a protective factor in the development of delinquency; (2) does the protective effect depend on whether disruptiveness is also present; and (3) does inhibition increase the risk of later depressive symptoms even if it protects against delinquency? METHODS: The subjects were boys from low socioeconomic status areas of Montreal, Quebec. Age 10- to 12-year predictors were peer-rated inhibition, withdrawal, and disruptiveness; age 13- to 15-year outcomes were self-rated depressive symptoms and delinquency. Eight age 10- to 12-year behavioral profiles were compared with 4 age 13- to 15-year outcome profiles. RESULTS: Inhibition seemed to protect disruptive and nondisruptive boys against delinquency. Disruptive boys who were noninhibited were more likely than chance to become delinquent; disruptive boys who were inhibited were not. Inhibition did not increase the risk for depression among disruptive boys. Among nondisruptive boys, only nondisruptive-inhibited boys were significantly less likely than chance to become delinquent. However, withdrawal was not protective. Disruptive-withdrawn boys were at the greatest risk for delinquency or delinquency with depressive symptoms. CONCLUSION: Inhibition and social withdrawal, although behaviorally similar, present different risks for later outcomes and, therefore, should be differentiated conceptually and empirically.

[Efficiency of a gambling prevention program for youths: results from the pilot study]. / Efficacité d'un programme de prévention des habitudes de jeu chez les jeunes: résultats de l'évaluation pilote.

UNLABELLED: A meta-analysis of North American studies indicates that the prevalence rate of pathological gambling varies between 4.4% and 7.4% among adolescents. Pathological gambling is thus not a phenomenon that suddenly appears once youths reach an adult age. On the contrary, significant contact with gambling occurs in childhood adolescence. For this reason, it is important to develop an effective gambling prevention program that will reduce the risk that youths will develop gambling problems. The information promoted in the prevention program our research team created and evaluated here teaches youths to recognize the traps of gambling activities, while enabling them to make an informed decision as to their eventual participation in those activities. The program is based on knowledge and recognition of key indices that can be easily identified as warning signs of a loss of control. It is predicted that youths who participate in this prevention program will improve their knowledge of gambling activities and will develop a more realistic attitude towards those activities than youths from a control group. The experimental group's problem-solving skills are also expected to improve. An experimental design (pre-test, post-test and follow-ups with control group) was used to evaluate the program's effectiveness. Overall, 1193 youths participated in this study. The prevention program involves three 60-minute meetings. The objectives of these meetings are the following: (meeting #1) improve youths' knowledge of gambling activities and help them acquire a more realistic attitude towards these activities; (meeting #2) teach a structured problem-solving approach to resist to peer-pressure; (meeting #3) inform youths of the consequences that may be associated with abusive participation in gambling and teach them to recognize warning signs of a loss of control over gambling habits. DEPENDENT VARIABLES: (a) knowledge of and attitudes towards gambling and gambling activities; (b) problem-solving skills; (c) frequency of participation in gambling activities; (d) discussion with relatives, friends and teachers regarding gambling activities and attention paid towards gambling habits among close friends and family. Participation in the gambling prevention program significantly improves youths' knowledge of the real probabilities of winning and the pitfalls included in gambling activities and favours the development of a more realistic attitude towards these activities. However, the participation in the prevention program does not help to improve their problem-solving skills. Nonetheless, it leads more youths to talk about gambling with their parents and teachers, and enables them to be more aware of the gambling habits of their friends and family. Finally, note that it was impossible to verify any decrease in gambling habits as the majority of participants (62%) were non or very occasional gamblers. However, no iatrogenic effect was observed on the frequency of participation in gambling activities. Aside the positive impact of the program on the attitudes and knowledge of students, participation in the preventive sessions contributed to create a dialogue with adults and increased youths' interest in the gambling habits of their friends and family. These discussions enabled the youths to validate the information they received during class, to consolidate what they learned during the prevention sessions, and favour the dissemination of this knowledge beyond the scope of the academic environment. The results obtained regarding youths' attitudes and knowledge demonstrate that attitude modification takes place progressively. However, once well assimilated, these new attitudes seem to take hold in a fairly durable way. On the other hand, acquisition of knowledge seems to take place immediately after the theoretical concepts are taught. Yet, they slightly decreased before stabilising a few months later. This suggests that assimilation of new knowledge may be optimized by the addition of an intervention session a couple of months after the end of the intervention. Even if it was impossible to verify any decrease in participants' gambling habits, it is possible to think that the impact of participation in the gambling prevention program could be observable and measurable within a few years. However, only a long-term follow-up study would make it possible to assess whether participation in the program does indeed contribute to decreasing gambling habits and the number of youths who regularly participate in gambling activities. Despite the non-significant results observed for problem-solving skills, it seems nonetheless important to include this component, which benefits from great theoretical support, especially within the framework of prevention programs targeting youths. However, the teaching method must be changed in order to maximize the intervention's effectiveness. Despite some methodological limitations observed during the evaluation of this program, the results obtained clearly demonstrate that participation in the prevention program significantly improves youths' attitudes and knowledge regarding gambling activities. The teaching of accurate knowledge and realistic attitudes towards gambling should help youths to recognize the cognitive traps inherent to gambling activities and thus contribute, over the long run, to decrease the number of youths with gambling problems.

Dispositional predictors of problem gambling in male adolescents.

OBJECTIVE: This study investigated the possible relationship between impulsivity in early adolescence and gambler status in late adolescence. METHOD: Impulsivity measures consisting of self-reports and teacher ratings were gathered from 754 boys in early adolescence, and their gambling status in late adolescence was assessed with a self-report measure. RESULTS: On both measures of impulsivity, nongamblers had the lowest scores, recreational gamblers had the next higher scores, low problem gamblers had still higher scores, and high problem gamblers had the highest scores. CONCLUSIONS: These findings support the DSM-IV classification of problem gambling as a deficit in impulse control.

Development of parasomnias from childhood to early adolescence.

OBJECTIVES: This study examines the prevalence and developmental changes of parasomnias and assesses gender differences, relationships between parasomnias, and associations with anxiety and family adversity using data collected during the course of a longitudinal study of a representative sample of children from Québec. METHOD: The present analyses are based on results available for 664 boys and 689 girls for whom mothers have completed questions concerning demographics, parasomnias, and anxiety level. For the prevalence and developmental aspects of parasomnias, prospective data were collected at annual intervals from 11 to 13 years old and retrospective data for the period between ages 3 and 10 years were collected when the children were 10 years old. RESULTS: Somniloquy, leg restlessness, and sleep bruxism are the most frequent parasomnias. More girls were afflicted with leg restlessness, while enuresis and somniloquy were more common in boys. High anxiety scores were found in children suffering from night terrors, somniloquy, leg restlessness, sleep bruxism, and body rocking. Parasomnias were unrelated to the index of family adversity. CONCLUSIONS: Although sleepwalking, night terrors, enuresis, and body rocking dramatically decreased during childhood, somniloquy, leg restlessness, and sleep bruxism were still highly prevalent at age 13 years, paralleling results found in adults. Sleepwalking, night terrors, and somniloquy are conditions often found together. The only robust gender difference was for enuresis. High anxiety scores in parasomnias are reported for the first time in a large, controlled study. Sociodemographic variables do not seem to play a major role in the occurrence of parasomnias.

Development of disturbing dreams during adolescence and their relation to anxiety symptoms.

STUDY OBJECTIVES: This work assesses the prevalence and development of disturbing dreams among adolescents and the association of these dreams with anxiety. DESIGN: Sex differences in prevalence were analyzed with chi-square analyses. Changes over time were assessed with Wilcoxon tests and cross-tabulation tables. Associations with anxiety and DSM-III-R symptoms were assessed with ANOVA designs. SETTING: N/A. PARTICIPANTS: A total of 610 boys and girls rated their recall of disturbing and normal dreams at both 13 and 16 years of age. Subgroups of subjects were evaluated for anxiety symptoms at age 13 and for DSM-III-R symptoms of separation anxiety (SA), overanxious disorder (OD) and generalized anxiety disorder (GAD) at age 16. INTERVENTIONS: N/A. MEASUREMENTS AND RESULTS: The recall of disturbing dreams was more prevalent for girls than for boys at both ages, and increased over time for girls while it decreased for boys. The recall of normal dreams was also more prevalent for girls at both ages, but this difference could not fully account for the difference in recall of disturbing dreams. Normal dream recall increased from age 13 to 16 for both sexes. The frequent occurrence of disturbing dreams was associated with anxiety at age 13 and with GAD, SA and OD symptoms at age 16 for both sexes. Evidence of more numerous OD symptoms for girls with frequent disturbing dreams suggests that this form of anxiety may partially account for the observed sex difference in disturbing dream prevalence. CONCLUSIONS: The findings highlight a prevalence of disturbing dreams that is especially marked for adolescent girls. Unlike previous cross-sectional studies, which have found the same sex difference, this longitudinal design also calls attention to within-subjects changes in disturbing dream recall. The results also confirm that the frequent recall of disturbing dreams is associated with pathological symptoms of trait anxiety-apparently even as young as 13 years of age. Further study of disturbing dreams may contribute to understanding of associated pathophysiological factors which, too, vary by sex (e.g., PTSD, insomnia, depression).

DSM-III-R and DSM-III criteria for conduct disorder in preadolescent girls: specific but insensitive.

OBJECTIVE: To determine whether DSM-III and DSM-III-R criteria for conduct disorder identify girls in the general population with early-onset, persistent, and pervasive antisocial behavior. METHOD: 2,251 girls, representative of all girls entering kindergarten in Qúebec, were assessed using parent and teacher ratings of antisocial behavior; a subsample was then rated for the next 6 years (ages 7 to 12) by parent and teacher. At age 10 years, the girls who been rated as antisocial in kindergarten, along with a random sample of those not rated as antisocial, were assessed for DSM-III and DSM-III-R diagnoses of conduct and oppositional defiant disorder using a structured psychiatric interview (Diagnostic Interview Schedule for Children) administered to the parent, teacher, and/or child (n = 381). RESULTS: Of the girls with early-onset, persistent, and pervasive antisocial behavior, 3% met DSM-III-R criteria and 22% met DSM-III criteria for conduct disorder. Conduct disorder was not diagnosed at all in girls who had not been initially rated as antisocial in kindergarten. Lowering the threshold for a DSM-III-R conduct disorder diagnosis to two symptoms and adding the criterion of violation of rules increased the rate of diagnosis to 35% in the pervasively antisocial girls but only to 1% in girls who did not have persistent antisocial behavior. CONCLUSIONS: DSM-III-R criteria for conduct disorder do not identify most preadolescent girls with early-onset, pervasive, and persistent antisocial behavior. Modifications to the DSM-III-R criteria resulted in increased sensitivity without a loss of specificity.

Problem drug and alcohol use in a community sample of adolescents.

OBJECTIVE: Epidemiological studies of illegal drug use in adolescents have examined frequency of drug use; a few have examined diagnoses or symptoms of drug abuse or dependence. This study examined problem use of illegal drugs, about which very little is known. METHOD: Adolescents (879 boys and 929 girls), mean age of 15.7 years, representative of the province of Québec, Canada, were asked about problem use of alcohol and illegal drugs. RESULTS: Almost one third had used illegal drugs more than 5 times. Of this group, more than 70% reported going to school high on drugs, and the majority reported playing sports while high and using drugs in the morning. In these drugs users, 94% of the boys and 85% of the girls reported at least 1 problem and two thirds of the boys and more than half of the girls reported 3 or more problems from illegal drugs. Marijuana was used by almost all subjects at the time of maximal drug use; hallucinogens were the second most commonly used drug. Alcohol was used more frequently than illegal drugs, but problem use was less common. CONCLUSIONS: Problem drug use is the norm among the large minority who use illegal drugs more than a few times, and drug use is commonly incorporated into 2 major routine activities of teenagers--school and sports.

Predicting girls' conduct disorder in adolescence from childhood trajectories of disruptive behaviors.

OBJECTIVE: To examine girls' developmental trajectories of disruptive behaviors during the elementary school years and to predict conduct disorder symptoms and diagnosis in adolescence with trajectories of these behaviors. METHOD: The sample was 820 girls from the province of Quebec followed over 10 years (1986-1996). A semiparametric mixture model was used to describe girls' developmental trajectories of teacher-rated disruptive behaviors between the ages of 6 and 12 years. The trajectories were used to predict conduct disorder symptoms and diagnosis when the girls were on average 15.7 years. RESULTS: Four groups of girls following trajectories with distinct levels of disruptive behaviors were identified: a low, medium, medium-high, and high trajectory. Prediction with the trajectories indicated that girls on the medium, medium-high, and high trajectories reported a significantly higher number of conduct disorder symptoms in adolescence. However, only the girls on the medium-high and high trajectories were at significantly higher risk to meet DSM-III-R criteria for conduct disorder, compared with girls in the low group (odds ratio: 4.46). More than two thirds of the girls with conduct disorder were in the medium or higher-level trajectories. CONCLUSION: The results suggest that there is an early-onset type of conduct disorder in girls.

Impulsivity predicts problem gambling in low SES adolescent males.

AIMS: This study investigated whether impulsivity measured in 12-14-year-olds could predict problem gambling in late adolescence, above and beyond other personality factors such as aggressiveness and anxiety. DESIGN: A prospective-longitudinal design was used, thus overcoming limitations of past studies which used concurrent or retrospective designs. PARTICIPANTS AND MEASUREMENTS: The sample included 154 boys living in economically deprived neighborhoods. Impulsivity measures comprised self-reports, teacher ratings and laboratory tasks, and were administered during early adolescence. Gambling behavior was assessed at age 17 using a self-report measure. Early gambling behavior and socio-demographic information were also collected for control purposes. FINDINGS: Results revealed that a self-report measure of impulsiveness and a card-sorting task significantly predicted problem gambling, even after controlling for socio-demographic variables, early gambling behavior and other personality variables such as aggressiveness and anxiety. Moreover, the predictive link held across all levels of aggressiveness and anxiety. Both impulsivity measures seemed to tap an inability to foresee negative consequences and an inability to stop responding despite unfavorable contingencies. CONCLUSION: These findings suggest that disinhibited individuals with response modulation deficits are at risk for problem gambling, thus supporting the DSM-IV classification of pathological gambling as an impulse control deficit.

Personal and familial characteristics of resilient sons of male alcoholics.

This study compared sons of male alcoholics (SOMAs) who had no problems with those who were abusing substances, those who had school problems, those who were delinquent and those who were multiproblem. Corresponding groups of non-SOMAs were also included. Groups were compared at ages 6, 10, 12 and 14 years on teacher- and peer-rated aggressiveness, hyperactivity, inattention, anxiety and prosociality; parent-rated temperament; parents' disciplinary practices; school performance; family socio-economic status; self-reported substance (ab)use and delinquency; and school performance (from school records). Differences between SOMAs and non-SOMAs were small. According to teachers and peers, no problem SOMAs and non-SOMAs were less aggressive-oppositional, inattentive and hyperactive than problem SOMAs and non-SOMAs. These effects differed as a function of age, however. Also, no problem SOMAs and non-SOMAs performed better in school than boys in the problem groups. We discuss the relevance of these findings for identifying factors that render children resilient and for early screening to select truly at risk SOMAs for prevention programs.