Louise Arseneault

A gradient of childhood self-control predicts health, wealth, and public safety

Policy-makers are considering large-scale programs aimed at self-control to improve citizens’ health and wealth and reduce crime. Experimental and economic studies suggest such programs could reap benefits. Yet, is self-control important for the health, wealth, and public safety of the population? Following a cohort of 1,000 children from birth to the age of 32 y, we show that childhood self-control predicts physical health, substance dependence, personal finances, and criminal offending outcomes, following a gradient of self-control. Effects of childrens self-control could be disentangled from their intelligence and social class as well as from mistakes they made as adolescents. In another cohort of 500 sibling-pairs, the sibling with lower self-control had poorer outcomes, despite shared family background. Interventions addressing self-control might reduce a panoply of societal costs, save taxpayers money, and promote prosperity.

Moderation of the effect of adolescent-onset cannabis use on adult psychosis by a functional polymorphism in the catechol-O-methyltransferase gene: longitudinal evidence of a gene X environment interaction.

BACKGROUND Recent evidence documents that cannabis use by young people is a modest statistical risk factor for psychotic symptoms in adulthood, such as hallucinations and delusions, as well as clinically significant schizophrenia. The vast majority of cannabis users do not develop psychosis, however, prompting us to hypothesize that some people are genetically vulnerable to the deleterious effects of cannabis. METHODS In a longitudinal study of a representative birth cohort followed to adulthood, we tested why cannabis use is associated with the emergence of psychosis in a minority of users, but not in others. RESULTS A functional polymorphism in the catechol-O-methyltransferase (COMT) gene moderated the influence of adolescent cannabis use on developing adult psychosis. Carriers of the COMT valine158 allele were most likely to exhibit psychotic symptoms and to develop schizophreniform disorder if they used cannabis. Cannabis use had no such adverse influence on individuals with two copies of the methionine allele. CONCLUSIONS These findings provide evidence of a gene x environment interaction and suggest that a role of some susceptibility genes is to influence vulnerability to environmental pathogens.

Cannabis use in adolescence and risk for adult psychosis: longitudinal prospective study.

Papers pp 1195, 1199 The strongest evidence that cannabis use may be a risk factor for later psychosis comes from a Swedish cohort study which found that heavy cannabis use at age 18 increased the risk of later schizophrenia sixfold. 1 2 This study could not establish whether adolescent cannabis use was a consequence of pre-existing psychotic symptoms rather than a cause. We present the first prospective longitudinal study of adolescent cannabis use as a risk factor for adult schizophreniform disorder, taking into account childhood psychotic symptoms3 antedating cannabis use. View this table: Association between cannabis use in adolescence and schizophrenia and depressive symptoms and disorders at age 26 (n=759), controlling for childhood psychotic symptoms and use of other drugs in adolescence The Dunedin multidisciplinary health and development study (a study of a general population birth cohort of 1037 individuals born in Dunedin, New Zealand, in 1972-3)4 has a 96% follow up rate at age 26. It obtained information on psychotic symptoms at age 11 and drug use at ages 15 and 18 from self reports and assessed …

Bullying victimization in youths and mental health problems: 'Much ado about nothing'?

Bullying victimization is a topic of concern for youths, parents, school staff and mental health practitioners. Children and adolescents who are victimized by bullies show signs of distress and adjustment problems. However, it is not clear whether bullying is the source of these difficulties. This paper reviews empirical evidence to determine whether bullying victimization is a significant risk factor for psychopathology and should be the target of intervention and prevention strategies. Research indicates that being the victim of bullying (1) is not a random event and can be predicted by individual characteristics and family factors; (2) can be stable across ages; (3) is associated with severe symptoms of mental health problems, including self-harm, violent behaviour and psychotic symptoms; (4) has long-lasting effects that can persist until late adolescence; and (5) contributes independently to childrens mental health problems. This body of evidence suggests that efforts aimed at reducing bullying victimization in childhood and adolescence should be strongly supported. In addition, research on explanatory mechanisms involved in the development of mental health problems in bullied youths is needed.

Bullying victimization uniquely contributes to adjustment problems in young children: a nationally representative cohort study

OBJECTIVE. It has been shown that bullying victimization is associated with behavior and school adjustment problems, but it remains unclear whether the experience of bullying uniquely contributes to those problems after taking into account preexisting adjustment problems. METHODS. We examined bullying in the Environmental Risk Study, a nationally representative 1994–1995 birth cohort of 2232 children. We identified children who experienced bullying between the ages of 5 and 7 years either as pure victims or bully/victims. We collected reports from mothers and teachers about children’s behavior problems and school adjustment when they were 5 years old and again when they were age 7. RESULTS. Compared with control children, pure victims showed more internalizing problems and unhappiness at school when they were 5 and 7 years. Girls who were pure victims also showed more externalizing problems than controls. Compared with controls and pure victims, bully/victims showed more internalizing problems, more externalizing problems, and fewer prosocial behaviors when they were 5 and 7 years. They also were less happy at school compared with control children at 7 years of age. Pure victims and bully/victims showed more behavior and school adjustment problems at 7 years of age, even after controlling for preexisting adjustment problems at 5 years of age. CONCLUSIONS. Being the victim of a bully during the first years of schooling contributes to maladjustment in young children. Prevention and intervention programs aimed at reducing mental health problems during childhood should target bullying as an important risk factor.

Maternal expressed emotion predicts children's antisocial behavior problems: using monozygotic-twin differences to identify environmental effects on behavioral development.

If maternal expressed emotion is an environmental risk factor for childrens antisocial behavior problems, it should account for behavioral differences between siblings growing up in the same family even after genetic influences on childrens behavior problems are taken into account. This hypothesis was tested in the Environmental Risk Longitudinal Twin Study with a nationally representative 1994-1995 birth cohort of twins. The authors interviewed the mothers of 565 five-year-old monozygotic (MZ) twin pairs and established which twin in each family received more negative emotional expression and which twin received more warmth. Within MZ pairs, the twin receiving more maternal negativity and less warmth had more antisocial behavior problems. Qualitative interviews were used to generate hypotheses about why mothers treat their children differently. The results suggest that maternal emotional attitudes toward children may play a causal role in the development of antisocial behavior and illustrate how genetically informative research can inform tests of socialization hypotheses.

Research Review: DSM-V Conduct Disorder--Research Needs for an Evidence Base.

This article charts a strategic research course toward an empirical foundation for the diagnosis of conduct disorder in the forthcoming DSM-V. Since the DSM-IV appeared in 1994, an impressive amount of new information about conduct disorder has emerged. As a result of this new knowledge, reasonable rationales have been put forward for adding to the conduct disorder diagnostic protocol: a childhood-limited subtype, family psychiatric history, callous-unemotional traits, female-specific criteria, preschool-specific criteria, early substance use, and biomarkers from genetics, neuroimaging, and physiology research. This article reviews the evidence for these and other potential changes to the conduct disorder diagnosis. We report that although there is a great deal of exciting research into each of the topics, very little of it provides the precise sort of evidence base required to justify any alteration to the DSM-V. We outline specific research questions and study designs needed to build the lacking evidence base for or against proposed changes to DSM-V conduct disorder.

Childhood Trauma and Children’s Emerging Psychotic Symptoms: A Genetically Sensitive Longitudinal Cohort Study

OBJECTIVE Using longitudinal and prospective measures of trauma during childhood, the authors assessed the risk of developing psychotic symptoms associated with maltreatment, bullying, and accidents in a nationally representative U.K. cohort of young twins. METHOD Data were from the Environmental Risk Longitudinal Twin Study, which follows 2,232 twin children and their families. Mothers were interviewed during home visits when children were ages 5, 7, 10, and 12 on whether the children had experienced maltreatment by an adult, bullying by peers, or involvement in an accident. At age 12, children were asked about bullying experiences and psychotic symptoms. Childrens reports of psychotic symptoms were verified by clinicians. RESULTS Children who experienced mal-treatment by an adult (relative risk=3.16, 95% CI=1.92-5.19) or bullying by peers (relative risk=2.47, 95% CI=1.74-3.52) were more likely to report psychotic symptoms at age 12 than were children who did not experience such traumatic events. The higher risk for psychotic symptoms was observed whether these events occurred early in life or later in childhood. The risk associated with childhood trauma remained significant in analyses controlling for childrens gender, socioeconomic deprivation, and IQ; for childrens early symptoms of internalizing or externalizing problems; and for childrens genetic liability to developing psychosis. In contrast, the risk associated with accidents was small (relative risk=1.47, 95% CI=1.02-2.13) and inconsistent across ages. CONCLUSIONS Trauma characterized by intention to harm is associated with childrens reports of psychotic symptoms. Clinicians working with children who report early symptoms of psychosis should inquire about traumatic events such as maltreatment and bullying.

Exposure to violence during childhood is associated with telomere erosion from 5 to 10 years of age: a longitudinal study

There is increasing interest in discovering mechanisms that mediate the effects of childhood stress on late-life disease morbidity and mortality. Previous studies have suggested one potential mechanism linking stress to cellular aging, disease and mortality in humans: telomere erosion. We examined telomere erosion in relation to childrens exposure to violence, a salient early-life stressor, which has known long-term consequences for well-being and is a major public-health and social-welfare problem. In the first prospective-longitudinal study with repeated telomere measurements in children while they experienced stress, we tested the hypothesis that childhood violence exposure would accelerate telomere erosion from age 5 to age 10 years. Violence was assessed as exposure to maternal domestic violence, frequent bullying victimization and physical maltreatment by an adult. Participants were 236 children (49% females; 42% with one or more violence exposures) recruited from the Environmental-Risk Longitudinal Twin Study, a nationally representative 1994–1995 birth cohort. Each childs mean relative telomere length was measured simultaneously in baseline and follow-up DNA samples, using the quantitative PCR method for T/S ratio (the ratio of telomere repeat copy numbers to single-copy gene numbers). Compared with their counterparts, the children who experienced two or more kinds of violence exposure showed significantly more telomere erosion between age-5 baseline and age-10 follow-up measurements, even after adjusting for sex, socioeconomic status and body mass index (B=−0.052, s.e.=0.021, P=0.015). This finding provides support for a mechanism linking cumulative childhood stress to telomere maintenance, observed already at a young age, with potential impact for life-long health.

Clinicopathological significance of psychotic experiences in non-psychotic young people: evidence from four population-based studies

BACKGROUND Epidemiological research has shown that hallucinations and delusions, the classic symptoms of psychosis, are far more prevalent in the population than actual psychotic disorder. These symptoms are especially prevalent in childhood and adolescence. Longitudinal research has demonstrated that psychotic symptoms in adolescence increase the risk of psychotic disorder in adulthood. There has been a lack of research, however, on the immediate clinicopathological significance of psychotic symptoms in adolescence. AIMS To investigate the relationship between psychotic symptoms and non-psychotic psychopathology in community samples of adolescents in terms of prevalence, co-occurring disorders, comorbid (multiple) psychopathology and variation across early v. middle adolescence. METHOD Data from four population studies were used: two early adolescence studies (ages 11-13 years) and two mid-adolescence studies (ages 13-16 years). Studies 1 and 2 involved school-based surveys of 2243 children aged 11-16 years for psychotic symptoms and for emotional and behavioural symptoms of psychopathology. Studies 3 and 4 involved in-depth diagnostic interview assessments of psychotic symptoms and lifetime psychiatric disorders in community samples of 423 children aged 11-15 years. RESULTS Younger adolescents had a higher prevalence (21-23%) of psychotic symptoms than older adolescents (7%). In both age groups the majority of adolescents who reported psychotic symptoms had at least one diagnosable non-psychotic psychiatric disorder, although associations with psychopathology increased with age: nearly 80% of the mid-adolescence sample who reported psychotic symptoms had at least one diagnosis, compared with 57% of the early adolescence sample. Adolescents who reported psychotic symptoms were at particularly high risk of having multiple co-occurring diagnoses. CONCLUSIONS Psychotic symptoms are important risk markers for a wide range of non-psychotic psychopathological disorders, in particular for severe psychopathology characterised by multiple co-occurring diagnoses. These symptoms should be carefully assessed in all patients.