There has been considerable debate in the UK in recent years about the propriety of using various forms of ‘involuntary out-patient treatment’ for some individuals with serious mental illness (Eastman, 1995; Dyre, 1998; Burns, 1999; Moncrieff & Smyth, 1999; Sugarman, 1999). While most jurisdictions in the US have statutes that support involuntary out-patient treatment (Torrey & Kaplan, 1995), its use remains controversial (Slobogin, 1994; Diamond, 1995; Torrey, 1997). Involuntary outpatient treatment was originally proposed as a solution to the ‘revolving door syndrome’ (Geller, 1996). It has also been recognised, however, that it may provide a solution to the clinical and ethical dilemmas of allowing individuals who are incapable of making treatment decisions to discontinue treatment, with predictable deterioration to the point where they may harm themselves or others (Geller, 1990). This paper provides a review of controlled studies that have examined whether involuntary treatment in the community is effective.