This article by Celestina Barbosa-Leiker, Sterling McPherson, and colleagues from Washington State University in the Pacific Northwest Node, reports on a study about the Adjective Rating Scale for Withdrawal (ARSW), an instrument commonly used to assess opiate withdrawal symptoms in clinical practice and research.
The study examined the factor structure of the ARSW, tested measurement invariance across gender and treatment groups, and assessed longitudinal measurement invariance across the clinical trial.
An analysis of data from National Drug Abuse Treatment Clinical Trials Network protocol CTN-0003, a randomized clinical trial comparing two tapering schedules for buprenorphine/naloxone, was performed. The ARSW was analyzed at baseline, end of taper, and 1-month follow-up.
A 1-factor model of the ARSW fit the data and demonstrated acceptable reliability. Measurement invariance was supported across gender and taper groups. Longitudinal measurement invariance was not found across the course of the trial, with baseline assessment contributing to the lack of invariance.
Conclusions: The ARSW appears to be measuring withdrawal equivalently across gender and buprenorphine/naloxone taper periods in opioid-dependent individuals. The authors recommend that researchers and clinicians using this tool analyze ARSW total scores across groups at each time point separately. If changeover time is of interest, change from post-treatment through follow-up may offer the most valid comparison; pre-treatment ARSW values may not be assessing withdrawal in the same way as post-treatment and follow-up values.
Citation: Barbosa-Leiker C, McPherson S, Marney MR, et al. Psychometric Properties of the Adjective Rating Scale for Withdrawal Across Treatment Groups, Gender, and Over Time. Journal of Substance Abuse Treatment 2013 (in press).