Objective: To examine hospital outcome measuresfor individuals with chronic and severe mental illnesses before and after their registration in an assertive community treatment (ACT) "A ssertive community treatment" (ACT) describes a l""\..model of community intervention for the treatment of individuals with severe and chronic mental illnesses. This model is derived from the "Training in Community Living" (later known as the "Program ofAssertive Community Treatment" or PACT) model. It was originally developed in Madison, Wisconsin, in the 1970s (1,2) and has since been adapted for other urban and rural North American settings (3-5). This model was initially developed as a response to one ofthe consequences of the deinstitutionalization movement of the 1960s, the "revolving-door" syndrome. ACT addresses this and other issues concerning people with severe mental illnesses by accepting that the client has a right to live in as normal an environment as possible but with intensive supports and services tailored to his or her needs. It assumes that, ifap ropriate and individualized services are provided, clients can live well in their preferred environment (out ofhospitalJ and that potential crises leading to hospital admissioncan'oe averted and treated within the community.Substantial research now exists on this treatment model, including reviews of ACT and its application to populations, both rural and urban, in the United States (US) (6-12).Cana· dian data are more limited, despite the implementation of ACT in several Canadian settings. One ofthe more receIftCa· nadian studies using a pre-post study design repo~.aQn a sample of 59 homeless individuals. Compared withpi~t~~\s· tration in ACT, symptoms decreased and social adju$t\1l.~nt and housing stability increased 9 months postregistratiOD (13); however, hospital use for the intervening timep¢ri od was not reported. Another Canadian study that usedrandom assignment to either ACT (n = 20) or a hospital-based pro' gram (n = 32) found 16% less hospital days for clients mthe ACT group compared with the hospital-based program (14), Since the sample sizes used in these studies are small,itisiln·I portant to replicate these fmdings in a larger cohort.