Evidence for interaction between genetic liability and childhood trauma in the development of psychotic symptoms.

PURPOSE: Whilst childhood trauma (CT) is a known risk factor across the spectrum of psychosis expression, little is known about possible interplay with genetic liability. METHODS: The TwinssCan Study collected data in general population twins, focussing on expression of psychosis at the level of subthreshold psychotic experiences. A multilevel mixed-effects linear regression analysis was performed including 745 subjects to assess the interaction between genetic liability and CT. The Symptom Checklist-90 (SCL-90-R) score of the co-twin was used as an indirect measure of genetic liability to psychopathology, while the Childhood Trauma Questionnaire Short-Form (CTQ-SF) was used to assess CT in the domains of physical, emotional and sexual abuse, as well as physical and emotional neglect. The Community Assessment of Psychic Experience (CAPE) questionnaire was used to phenotypically characterize psychosis expression. RESULTS: In the model using the CAPE total score, the interaction between CT and genetic liability was close to statistical significance (χ2 = 5.6, df = 2, p = 0.06). Analyses of CAPE subscales revealed a significant interaction between CT and genetic liability (χ2 = 8.8, df = 2, p = 0.012) for the CAPE-negative symptoms subscale, but not for the other two subscales (i.e. positive and depressive). CONCLUSION: The results suggest that the impact of CT on subthreshold expression of psychosis, particularly in the negative subdomain, may be larger in the co-presence of significant genetic liability for psychopathology.

Relationship between Bullying, Substance Use, Psychiatric Disorders, and Social Problems in a Sample of Kenyan Secondary Schools.

We aimed to investigate how direct bullying and victimization relate with substance use, the presence of psychiatric disorders, poor school performance, disruptive behaviors, and social problems among secondary school students. A cross-sectional study was conducted in 20 randomly selected mixed-day secondary school students in forms one to three in Machakos County, equivalent to students in grades 1 to 11. From a random starting point, every sixth student in the class was invited to participate. The Drug Use Screening Inventory (revised) (DUSI-R) and the Olweus Bully/Victim Questionnaire (OBVQ) were administered in a classroom-setting by trained research assistants with experience in data collection. Four categories, i.e., bully only, bully-victim, victim only, and neither bully nor victims (neutrals) were developed and problem density scores computed. Descriptive statistics, bivariate, and multinomial logistic regression analysis summarized the findings. Of the 471 students, 13.6% had not experienced bullying problems. Bully-victim was the most prevalent form of bullying. No significant gender differences were reported across categories. Bully-victims reported significant higher problem density scores in eight out of the nine problem domains, and effect sizes of the differences in problem scores between neutrals and bully-victims were larger compared with other categories. Behavioral and family system problem scores retained a significant relationship with bully-victim category (p < 0.001). A high prevalence of bullying problems was documented in both genders. However, bully-victims had a higher risk of multiple negative individual and environmental and social problems. Assessment of bullying problems is an indirect route to identifying significant youth problems. Bullying interventions should be multifaceted to address psycho-socio-behavioral problems.

The interaction between cannabis use and the Val158Met polymorphism of the COMT gene in psychosis: A transdiagnostic meta - analysis.

BACKGROUND: Neither environmental nor genetic factors are sufficient to predict the transdiagnostic expression of psychosis. Therefore, analysis of gene-environment interactions may be productive. OBJECTIVE: A meta-analysis was performed using papers investigating the interaction between cannabis use and catechol-O-methyl transferase (COMT) polymorphism Val158Met (COMTVal158Met). DATA SOURCES: PubMed, Embase, PsychInfo. STUDY ELIGIBILITY CRITERIA: All observational studies assessing the interaction between COMTVal158Met and cannabis with any psychosis or psychotic symptoms measure as an outcome. STUDY APPRAISAL AND SYNTHESIS METHODS: A meta-analysis was performed using the Meta-analysis of Observational Studies in Epidemiology guidelines and forest plots were generated. Thirteen articles met the selection criteria: 7 clinical studies using a case-only design, 3 clinical studies with a dichotomous outcome, and 3 studies analysing a continuous outcome of psychotic symptoms below the threshold of psychotic disorder. The three study types were analysed separately. Validity of the included studies was assessed using "A Cochrane Risk of Bias Assessment Tool: for Non-Randomized Studies of Interventions". RESULTS: For case-only studies, a significant interaction was found between cannabis use and COMTVal158Met, with an OR of 1.45 (95% Confidence Interval = 1.05-2.00; Met/Met as the risk genotype). However, there was no evidence for interaction in either the studies including dichotomous outcomes (B = -0.51, 95% Confidence Interval -1.72, 0.70) or the studies including continuous outcomes (B = -0.04 95% Confidence Interval -0.16-0.08). LIMITATION: A substantial part of the included studies used the case-only design, which has lower validity and tends to overestimate true effects. CONCLUSION: The interaction term between cannabis use and COMTVal158Met was only statistically significant in the case-only studies, but not in studies using other clinical or non-clinical psychosis outcomes. Future additional high quality studies might change current perspectives, yet currently evidence for the interaction remains unconvincing.