Assessment of alcohol and tobacco use in psychotherapy: validation of the german self-report ASSIST alcohol and tobacco subscales in an outpatient setting.

Alcohol and tobacco use are leading causes of preventable mortality and transdiagnostic risk factors for poor health, especially in comorbid mental disorders. Identification and treatment in German healthcare remain inadequate. The WHO ASSIST is a brief screening tool for substance use, but the German self-report version has not been systematically validated for alcohol and tobacco. METHODS: In a psychotherapeutic outpatient sample (N = 553; mean age 34.9, SD = 13.4, range 18-74; 60 % female), we evaluated (i) concurrent, (ii) construct, (iii) discriminative validity, and (iv) diagnostic accuracy of the alcohol (ASSISTA) and tobacco (ASSISTT) subscales. RESULTS: Regarding concurrent validity, ASSISTA strongly correlated with AUDIT and showed weak correlation with clinical judgement, whereas ASSISTT correlated with FTND but not with clinical judgement. Construct validity was demonstrated by acceptable internal consistency and small correlations with ICD-10 alcohol and tobacco diagnoses. Discriminative validity was good for both subscales. Diagnostic accuracy analyses indicated that optimal cutoff values were substantially lower than the manual thresholds (alcohol 3.5/8.5 vs. 11/27, tobacco 5.5 vs. 27). DISCUSSION: Our results support the validity of the German ASSISTA/T subscales. Comparison with established measures highlights clinical utility. ASSISTT's lack of correlation with clinical judgement suggests smoking might be under-recognized without standardized screening. We propose empirically derived cutoff values to improve sensitivity for detecting clinically relevant substance use in outpatient psychotherapy settings.