Reasons for substance use and vulnerability factors in patients with substance use disorder and anxiety or mood disorders.

This cross-sectional study examined the reasons for substance use and the presence of vulnerability factors such as substance sensitivity, sensation seeking, and symptoms related to the attention deficit hyperactivity disorder (ADHD) in patients with substance use disorder (SUD) and comorbid mood and anxiety disorders by using the Structured Clinical Interview for the Spectrum of Substance Use (SCI-SUBS), a novel instrument designed to explore the spectrum of substance use and its clinical correlates. Study participants included 61 patients with SUD and mood or anxiety disorder, and two comparison groups including 35 patients with SUD only and 50 controls not in treatment for mental disorders or SUD. We found that patients with co-morbid mood or anxiety disorder had significantly higher scores on the SCI-SUBS domains 'substance sensitivity' and 'self-medication' as compared to those with SUD only. Scores on 'sensation seeking' and 'ADHD' domains were similar between both groups of patients and higher than in controls. Patients with comorbid mood or anxiety disorders showed a higher sensitivity to substances and were more prone to self-medication than those with SUD only. These characteristics should be taken into account in the diagnostic assessment and in long-term treatment to decrease the risk of relapse.