The concurrent development of psychological distress, heavy episodic drinking, and daily smoking from adolescence to midlife in two cohorts

Background Heavy substance use, such as alcohol and tobacco use, is more prevalent among people with poor mental health. Despite the well-established correlation between substance use and mental health, the development of this association over time is unclear. The aim of this study was to examine the development and co-occurrence of psychological distress (mainly depressive and anxiety symptoms), heavy episodic drinking (HED) and daily smoking from adolescence to adulthood. Methods Two prospective longitudinal studies, the Stress, Development and Mental Health Study (TAM, N=2194) and the FinnTwin16 Study (N=5563), have followed participants from adolescence to adulthood (TAM ages 16-52, FinnTwin16 ages 16-35) using survey questionnaires. Latent class analysis was used to obtain joint trajectories of distress, HED and daily smoking. Results This study identified several different patterns of how HED, daily smoking and psychological distress cluster across time from adolescence to adulthood. In both examined cohorts, distinct groups of i) low levels of all three examined health concerns, ii) high levels of all three concerns, and iii) high distress and low-to-moderate substance use were found. In the older TAM cohort with longer follow-up time, a group indicating iv) increasing HED and a group indicating v) all on average level, with a peak in smoking, were also found. Conclusions Found variations set requirements for substance use and mental health services to target interventions for different groups to address all three major public health problems.