the northwestern ontario concurrent disorders program (nocdp) offers a multidisciplinary, assertive community treatment approach to clients with concurrent disorders, substance dependence and co-morbid severe and persistent axis i and/or axis ii disorder. substance use in a psychiatric population lessens the effectiveness of treatment, increases the symptom severity of the mental illness, and leads to less successful treatment outcomes. accordingly, these individuals need programming tailored specifically to their psychopathology, substance(s) of choice, and social supports. the present research examines the population that nocdp serves, and the effectiveness of its programming. client symptom reporting, reported impact of substance use, number of hospitalizations, legal activity, residential status, education/employment activity and income level are used as measures of treatment success. while improvements within groups were indicated on some measures, significant differences between groups were not found. level of functioning of nocdp clients did improve over time, but interpretation of the data was complicated by design limitations related to the naturalistic nature of the study.