AN EVALUATION OF DSM-III-R AND ICD-10 BENZODIAZEPINE DEPENDENCE CRITERIA USING RASCH MODELING

Aims. To evaluate the homogeneity of the elements of the Substance Dep endence Syndrome (SDS) as applied to benzodiazepines (BZDs) by Rasch m odelling. Measurements. The Rasch scaling model teas applied to data o btained by administering the SCAN (Schedules for Clinical Assessments in Neuropsychiatry) substance dependence sections. Subsequently, Rasch -homogeneous sets of DSM-III-R and ICD-10 BZD dependence criteria were assessed for subject and item discriminability. To support their cons truct validity a theoretical rationale teas formulated based on the Ra sch scale values. Participants. A heterogeneous sample of 599 outpatie nt BZD users. Findings, Only particular subsets of the DSM-III-R and I CD-10 BZD dependence criteria met the requirements for Rasch-homogenei ty, which appears to be due to medical aspects of BZD use. The subject and item discriminability results were sufficiently goad. Conclusions . The DSM-III-R and ICD-10 BZD dependence constructs may need to be re defined The use of a BZD dependence severity model based on a Rasch-ho mogeneous scale appears to have greater clinical value than a dichotom ous diagnostic model based on an arbitrary cut-off point. We recommend Rasch modelling to investigate the homogeneity of the elements of the SDS across other psychoactive substances.