The influence of childhood aspirations on the risk of developing psychotic disorders, substance use disorders, and dual diagnosis in adulthood based on the Metropolit 1953 Danish Male Birth Cohort

The study aims to investigate the association of aspiration for future occupation, socioeconomic position, and intellectual abilities with risk of dual diagnosis, psychosis, substance use disorder (SUD) in later life, and to explore if social and intellectual disadvantage modify any effect of childhood aspirations on outcomes. The study included 7177 Danish boys born in 1953. We investigated childhood aspirations (preference regarding future occupation), socioeconomic position (paternal social group), and intellectual abilities (Härnquist intelligence score) on outcomes with dual diagnosis, psychotic disorder, or SUD in Danish registers. Combinations of variables were used for a two-way and three-way analysis (high and low levels of exposure variables). Cox regression with age as the underlying time scale was used for analysis. The separate analysis showed no associations between childhood aspirations and outcomes. Boys with low intelligence scores had an increased risk of developing psychotic disorders (aHR 1.5, 95% CI 1.1–2.1) and SUD (aHR 1.8, 95% CI 1.5–2.1) compared to high intelligence scores. The interaction analyses showed that individuals with a combination of low intelligence score, high aspirations, and/or high paternal social group might have an increased risk of developing dual diagnosis, psychotic disorders, or SUD in later life. This result should be interpreted with caution as interaction variables were not overall significant with the outcome of dual diagnosis or psychotic disorder. The findings suggest that childhood abilities and social position could be associated with the development of psychotic disorders and SUD in later life, however, further studies are needed to address the temporality of the association to gain an understanding of the underlying mechanism of the association.