Scalability, reliability, and validity of the benzodiazepine dependence self-report questionnaire in outpatient benzodiazepine users

As there is no multidimensional instrument available that reflects the severity of benzodiazepine (BZD) dependence comprehensively, the Benzodiazepine Dependence Self-Report Questionnaire (Bendep-SRQ) was developed and investigated. The Bendep-SRQ, Symptom Checklist-90 (SCL-90), Schedules for Clinical Assessments in Neuropsychiatry (SCAN), and Addiction Severity Index-Revised (ASI-R) were administered to 115 general practice (GP) patients, 124 psychiatric outpatients, and 33 self-help patients who were using BZDs. Factor and Rasch analyses were applied to construct scales. Reliability assessments were made in terms of subject discriminability, item discriminability, and test-retest stability. To support the construct validity of the scales, theoretical rationales were required to explain the specific item order provided by the Rasch scale values. To assess the concurrent and discriminant validity, a matrix consisting of the above-mentioned measures was factor-analyzed. Four Rasch-homogeneous scales were delineated: problematic use, preoccupation, lack of compliance, and withdrawal. Nearly all subject discriminability, item discriminability, and test-retest results indicated good reliability. A BZD dependence factor was extracted with high loadings for the Bendep-SRQ scales and the concurrent measures. The discriminant measures had high loadings on other factors. The scalability, reliability, and validity of the Bendep-SRQ scales appeared to be good. The Bendep-SRQ shows great promise as a useful and easily manageable instrument for assessment of the severity of BZD dependence in clinical practice and scientific research.