Comorbid Attention-Deficit/Hyperactivity Disorder and Mood Disorder in a South African Sample of Substance Use Disorder Patients

Background: The brain reward circuitry is thought to underlie the co-occurrence of attention-deficit/hyperactivity disorder (ADHD) and substance use disorder (SUD) and to possibly impact mood disorders. This study aimed to establish if any difference existed in the severity of depression symptomology between SUD comorbidity with and without ADHD. Methods: A multi-centre, cross-sectional comparison study design drew study participants from substance use treatment facilities within South Africa. The participants were screened for ADHD and depression, with the selective application of a confirmatory ADHD diagnostic interview. The participants were diagnostically grouped according (SUD + ADHD, SUD - ADHD) to an application of a 2 x 2 x 3 ANOVA model. Results: A significant main effect of ADHD diagnosis and gender on depressive symptoms was identified. Post hoc analysis revealed that only male ADHD subjects had significantly higher scores on the Beck scale than non-ADHD males. Conclusions: Co-occurring disorder (COD) prevalence rates were higher than most other South African studies. The aggravation of ADHD on mood disorder symptom severity is consistent with the existing literature; however, further investigation is warranted to determine if the interaction of gender remains only significant for men with a lager sample size. The identified COD prevalence rate may contrast with other South Africa studies, emphasising the need for comprehensive psychiatric comorbidity screening in SUD treatment settings.