Religiousness and self-control in patients with substance use disorder (SUD) and comorbid attention deficit/hyperactivity disorder (ADHD).

Background: Religiousness has been positively associated with better mental health and stronger self-control, including in patients with substance use disorders (SUDs) or attention deficit/hyperactivity disorder (ADHD). However, data on religiousness in patients with SUD and comorbid ADHD are lacking.

Objective: This study aims to test in patients with SUD and comorbid ADHD whether (1) religiousness is negatively associated with SUD and ADHD symptom severity, and (2) self-control mediates the assumed negative association of religiousness with SUD and ADHD symptom severity.

Methods: In an international cohort study, baseline religiousness, self-control, SUD and ADHD symptom severity, and craving were assessed with self-report questionnaires and structured clinical interviews in 578 treatment-seeking SUD patients with comorbid adult ADHD (SUD + ADHD). Data were analyzed using structural equation modeling (SEM).

Results: Stronger self-control wad associated with lower severity of both ADHD and SUD, but higher religiousness was only associated with lower severity of ADHD. This association was not mediated by self-control.

Conclusions: Religiousness may have a salutary relationship with ADHD severity, but not with SUD severity. While self-control was associated with lower symptom severity for both co-occurring conditions, it may not be involved in the potentially salutary effects of religiousness in patients with SUD + ADHD.