 Drug and alcohol abuse by people with severe and persistent mental illness SPMI is one of the most significant problems facing the public mental health system. We have been conducting a project to develop a multifaceted treatment for substance abuse in dual disordered patients Behavioral Treatment for Substance Abuse in Schizophrenia; BTSAS. Results have shown that the treatment is well-accepted by patients and has a significant effect on drug use. While BTSAS has been effective at retaining subjects and fostering reduced drug use, a major problem that occurred was low rates of engagement. The main purpose of this study is to determine if BTSAS is more effective in reducing drug use than a supportive control treatment and to determine if adding a case management component Critical Time Intervention; CTI will increase treatment engagement and retention in BTSAS. 