Impulsivity as a predictor of treatment outcome in individuals with comorbid social anxiety and alcohol use disorder

Social anxiety is frequently comorbid with alcohol use disorders and their co-occurrence results in greater severity, disability and poorer treatment outcomes. However, there is a lack of studies examining factors that may impact treatment outcome for these co-occurring problems. The purpose of this study was to examine the association between impulsivity and both social anxiety and alcohol use outcomes within a clinical sample of adults diagnosed with social anxiety disorder and alcohol use disorders (N = 60) who participated in a trial of Motivational Interviewing and Cognitive Behavioural Therapy (MI/CBT) for combined treatment for alcohol problems and social anxiety or alcohol problems only. Random effects regression was used to examine the association between impulsivity and the rate of improvement in four treatment outcomes: social anxiety symptoms, severity of alcohol dependence, drinks per day and number of drinking days. Higher trait rash impulsivity was associated with better social anxiety outcomes controlling for other variables. The impact of impulsivity on alcohol-related outcomes was mixed, with weak evidence suggesting that individuals high in rash impulsivity and reward drive at baseline improved to a greater extent over time in severity of alcoholdependence. Additionally, baseline impulsivity was predictive of better treatment outcomes in quantity, but not frequency of alcohol use. In contrast, alcohol expectancies did not impact degree of change over time for any social anxiety or alcohol outcome measure. Understanding the impact of impulsivity on treatment outcomes may have prognostic utility and suggests that individuals with co-occurring social anxiety and alcohol use disorders, high on imp ulsivity may particularly benefit from the skills imparted through CBT.