Mediating effect of depression on the association between inattention or hyperactivity with the severity of substance dependence: the role of self-efficacy.

Substance use disorder (SUD) is a significant public health issue impacting millions of people worldwide. Many mental health disorders are often comorbid with SUD, and they can influence its severity. The aim of this study was to examine the relationship of adult attention deficit hyperactivity disorder (ADHD) symptoms, depressive symptoms, the level of self-efficacy and the severity of SUD. This study analyzed data from 117 participants with SUD. The severity of SUD, ADHD symptoms, depressive symptoms, and self-efficacy were measured. A moderated mediation model was used to evaluate the effects of adult ADHD and depressive symptoms on the severity of SUD, as well as the association of self-efficacy on depression. We found that the direct positive association between ADHD symptoms and substance dependence, as well as an indirect positive association mediated by depression. Higher self-efficacy in resisting illicit substances weakened the association of depression, indicating a negative moderating effect. Self-efficacy compromises the association between ADHD symptoms and substance dependence. Early interventions to enhance self-efficacy and reduce depression may be beneficial.