To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.addbeh.2006.06.026 Byline: Kenneth R. Conner (a), Rebecca J. Houston (b), Luke M. Sworts (a), Sean Meldrum (c) Keywords: Opiate dependence; Aggression; Reliability; Measure; Methadone maintenance Abstract: The purpose of the study was to evaluate the internal consistency and test-retest reliability of the Impulsive Aggression (IA) and Premeditated Aggression (PM) scales of the Impulsive-Premeditated Aggression Scale (IPAS) in male and female substance-dependent patients, and to compare the findings to those obtained on widely used, validated measures of aggression. Using a sample of 121 patients (61 women) in methadone maintenance treatment, 69 (35 women) of which were re-evaluated after a minimum of 2weeks, the IPAS scales showed acceptable internal consistency ([alpha] .72) and test-retest reliability (ICC.54). These results were comparable to the other aggression measures, and results among women were comparable to men. This was the first study to examine the IPAS scales in a substance use population, to contain a sufficient sample of women for sub-analyses, and to examine the stability of the measure. Findings support the internal consistency and test-retest reliability of the IPAS in male and female opiate-dependent individuals. Author Affiliation: (a) University of Rochester Medical Center, Center for the Study and Prevention of Suicide, 300 Crittenden Blvd, Rochester, NY 14642, USA (b) Research Institute on Addictions, University at Buffalo, 1021 Main St, Buffalo, NY 14203, USA (c) University of Rochester Medical Center, Department of Family Medicine, 1381 South Avenue, Rochester, NY 14620, USA