There has been much international impetus to address the importance of identifying and treating clients experiencing both a substance use
disorder and a mental disorder in treatment settings. Gaps in the literature still exist after a decade of research into this area. There is little
research on the prevalence of co-occurring mental disorders (CODs) in the residential alcohol and other drug (AOD) treatment modality. In
this study, the mental disorder status of 278 participants resident in AOD treatment settings across Australia was estimated using the
Addiction Severity Index—Self Report (J.S. Cacciola, A. Pecoraro, & A.I. Alterman, 2008) and the Mental Health Screening Form III (J.F.X.
Carroll & J.J. McGinley, 2001). The estimated rate of diagnosable Axis I mental disorder comorbidity varied from 64% to 71% depending
upon which cutoff score was used with the MHSF-III. Missing data emerged as a major limitation of the self-report version of the Addiction
Severity Index psychiatric composite score in this population. © 2011 Elsevier Inc. All rights reserved.