The Addiction Severity Index medical and psychiatric composite scores measure similar domains as the SF-36 in substance-dependent veterans: concurrent and discriminant validity

BACKGROUND: Recently attention has focused on the assessment of functional health status in substance-dependent individuals. The addiction severity index (ASI) is a widely used assessment instrument that includes scales to reflect current medical and psychiatric status. This study examines the concurrent validity of these ASI composite scores in relation to the short form 36-item health survey (SF-36), a well-established measure of health-related quality of life/functional health status. METHODS: Veterans (n=674) were assessed at admission to substance dependence treatment. Correlations were performed between ASI composite scores and SF-36 scales and the physical and mental summary components (PSC and MSC, respectively). Areas under receiver operating characteristic (ROC) curves determined the descriminative ability of the ASI composites to ascertain impairment. RESULTS: The ASI medical composite score demonstrated robust correlations with the four SF-36 scales that relate to physical health and with the PCS. The ASI psychiatric composite score had robust correlations with the four SF-36 scales related to mental health and with the mental component summary (MCS). ROC curves indicated that the ASI medical (AUC=0.83) and psychiatric composites (AUC=0.90) accurately detected subjects with impairment. CONCLUSIONS: ASI medical and psychiatric composite scores provide effective initial screening for patients with impaired functional status as measured by the corresponding SF-36 component summary scores.