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

Abstract

As there is no multidimensional instrument available which reflects the severity of BZD dependence comprehensively, the Benzodiazepine Dependence Self-Report Questionnaire (Bendep-SRQ) was developed and investigated. The Bendep-SRQ, Symptom Checlist-90, Schedules for Clinical Assessments in Neuropsychiatry and Addiction Severity Index-Revised were administered to 115 general practice patients, 124 psychiatric outpatients and 33 self-help patients who were using benzodiazepines. Factor and Rasch analyses were applied to construct scales. Reliability assessments were carried out 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 mentioned measures was factor-analyzed. Four Rasch-homogeneous scales were delineated: 'Problematic Use', 'Preoccupation', 'Lack of Compliance' and 'Withdrawal'. Nearly all the subject discriminability, item discriminability and and test-retest results indicated good reliability. A Benzodiazepine 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 the assessment of the severity of Benzodiazepine Dependence in clinical practice and scientific research.