Genetic and environmental contributions to psychopathological symptoms in adulthood: Clarifying the role of individual and parental risk factors.

Psychopathology-related suicide attempts and deaths are increasing, and the research focus remains on mental disorder in childhood and adolescence. We examined the genetic and environmental contributions to internalizing, externalizing, and general psychopathological distress to clarify the role of individual/parental risk factors for suicide in young adults. Data from 1206 young adults were obtained from a publicly available dataset from the Human Connectome Project. Heritability estimates were analyzed by twin modelling using OpenMx and data from a subsample of 402 monozygotic and dizygotic twins. The estimated prevalence of psychopathological symptoms ranged from 9 to 16%. The heritability of internalizing, externalizing, and general psychopathological distress reached significance, with estimates ranging from 22 to 46%. Shared (common) environments contributed to aggressive behavior (30 %). Determining factors for psychopathological distress (internalizing, externalizing, general) were evaluated using logistic regression analysis. Household income (<$50,000), childhood conduct problems, and maternal drug or alcohol problems were common risk factors of internalizing, externalizing, and general psychopathological distress. Marijuana dependence and maternal anxiety were additional risk factors of externalizing distress. The presence of alcohol and maternal drug or alcohol problems was linked to general psychopathological distress. The results highlight risk factors associated with psychopathological symptoms that should be considered in the early detection of high-risk groups and implementation of family-based interventions. Providing continuous care and/or follow-up in at-risk children and young adults may improve mental health and well-being.