Addressing aggressive behavior in adolescence is a key step toward preventing violence and associated social and economic costs in adulthood. This study examined the secondary effects of the personality-targeted substance use preventive program Preventure on aggressive behavior from ages 13 to 20.

In total, 339 young people from nine independent schools (M age = 13.03 years, s.d. = 0.47, range = 12–15) who rated highly on one of the four personality traits associated with increased substance use and other emotional/behavioral symptoms (i.e. impulsivity, anxiety sensitivity, sensation seeking, and negative thinking) were included in the analyses (n = 145 in Preventure, n = 194 in control). Self-report assessments were administered at baseline and follow-up (6 months, 1, 2, 3, 5.5, and 7 years). Overall aggression and subtypes of aggressive behaviors (proactive, reactive) were examined using multilevel mixed-effects analysis accounting for school-level clustering.

Across the 7-year follow-up period, the average yearly reduction in the frequency of aggressive behaviors (b = −0.42; 95% confidence interval [CI] −0.64 to −0.20; p < 0.001), reactive aggression (b = −0.22; 95% CI 0.35 to −0.10; p = 0.001), and proactive aggression (b = −0.14; 95% CI −0.23 to −0.05; p = 0.002) was greater for the Preventure group compared to the control group.

The study suggests a brief personality-targeted intervention may have long-term impacts on aggression among young people; however, this interpretation is limited by imbalance of sex ratios between study groups.

It has not yet been determined if the commonly reported cannabis–psychosis association is limited to individuals with pre-existing genetic risk for psychotic disorders.

We examined whether the relationship between polygenic risk score for schizophrenia (PRS-Sz) and psychotic-like experiences (PLEs), as measured by the Community Assessment of Psychic Experiences-42 (CAPE-42) questionnaire, is mediated or moderated by lifetime cannabis use at 16 years of age in 1740 of the individuals of the European IMAGEN cohort. Secondary analysis examined the relationships between lifetime cannabis use, PRS-Sz and the various sub-scales of the CAPE-42. Sensitivity analyses including covariates, including a PRS for cannabis use, were conducted and results were replicated using data from 1223 individuals in the Dutch Utrecht cannabis cohort.

PRS-Sz significantly predicted cannabis use (p = 0.027) and PLE (p = 0.004) in the IMAGEN cohort. In the full model, considering PRS-Sz and covariates, cannabis use was also significantly associated with PLE in IMAGEN (p = 0.007). Results remained consistent in the Utrecht cohort and through sensitivity analyses. Nevertheless, there was no evidence of a mediation or moderation effects.

These results suggest that cannabis use remains a risk factor for PLEs, over and above genetic vulnerability for schizophrenia. This research does not support the notion that the cannabis–psychosis link is limited to individuals who are genetically predisposed to psychosis and suggests a need for research focusing on cannabis-related processes in psychosis that cannot be explained by genetic vulnerability.

Abnormalities in reward circuit function are considered a core feature of addiction. Yet, it is still largely unknown whether these abnormalities stem from chronic drug use, a genetic predisposition, or both.

In the present study, we investigated this issue using a large sample of adolescent children by applying structural equation modeling to examine the effects of several dopaminergic polymorphisms of the D1 and D2 receptor type on the reward function of the ventral striatum (VS) and orbital frontal cortex (OFC), and whether this relationship predicted the propensity to engage in early alcohol misuse behaviors at 14 years of age and again at 16 years of age.

The results demonstrated a regional specificity with which the functional polymorphism rs686 of the D1 dopamine receptor (DRD1) gene and Taq1A of the ANKK1 gene influenced medial and lateral OFC activation during reward anticipation, respectively. Importantly, our path model revealed a significant indirect relationship between the rs686 of the DRD1 gene and early onset of alcohol misuse through a medial OFC × VS interaction.

These findings highlight the role of D1 and D2 in adjusting reward-related activations within the mesocorticolimbic circuitry, as well as in the susceptibility to early onset of alcohol misuse.

In order to support service planning of the youth program of the East of Montreal Health and Social Services Board, and potentially of the other twenty-five programs across the Quebec province, our hospital-based Health Technology Assessment (HTA) unit was asked to bring evidence of the effective interventions for five most common mental disorders in children and young populations, namely anxio-depressive disorders, attention deficit and hyperactivity disorder, oppositional and conduct disorders, substance abuse disorders, and suicide attempts.

A review of reviews was conducted for the five disorders in young populations aged 6 to 25 years. This was based exclusively on systematic reviews and meta-analysis of a minimum two randomized-controlled trials. The review was completed with examples of Quebec's good practices in youth mental health gathered from personal research experience of clinical researchers involved in the project. The project involved collaboration with three other hospital units and provincial HTA agencies.

No review supporting screening and early detection for the five disorders was identified. Prevention, however, was better covered in the literature, and a clear distinction was made between universal, targeted and indicated interventions. In general, targeted and indicated prevention interventions were effective in the case of anxio-depressive (1) and substance use disorders, while universal prevention strategies seemed to reduce suicide attempts and suicide ideation (2). Effective treatments also exist for these mental disorders. In general, psychotherapies dominated for anxio-depressive and substance use disorders; parental skills dominated in oppositional disorders, whilst pharmacological treatment dominated in attention deficit and hyperactivity disorder (3). Evidence was limited for suicide attempts. The overview of Quebec's good practices allowed identification of interventions or practices already in use in the province.

The review summarized effective interventions for five most common mental disorders in young populations. It also permitted to identify several research gaps, and therefore research recommendations were formulated for the province's health research agency.