The results of this literature review ire presented in both narrative form and a meta-analysis. A meta-analysis was set up for the 52 studies with controls. 23 studies were excluded where the outcome criteria were unclear, where the raw numbers were not reported, or where the original sample was not clearly specified before attrition. There is strong evidence for the effectiveness of lerapeutic community treatment apparent from these studies. This systematic intemational literature review has led us to conclude that therapeutic communities have not produced the amount or quality of research literature that we might have expected, given the length of time they have been in existence, and the quality of staff we know exists and has existed in therapeutic communities.