A literature review includes 12 studies published in the United States comparing crime rates of discharged mental patient samples with the general population: the methodological strengths and weaknesses of those studies are summarized in tabular form. Variations in time, setting, and geographic locale makes comparisons among studies difficult. The studies are further analyzed for sample size; diagnostic categories (e.g., alcoholics and drug addicts were included along with schizophrenics); criteria for crime; and criminal recidivism. Researchers almost universally neglected to control for important crime variables such as age, sex, race, socioeconomic level, and marital status, as demanded by rigorous scientific procedures. While some indications point to higher criminality among former mental patients, it is possible that defensive reactions to economic, physical, and verbal assaults perpetrated upon them in hostile community settings may account for it. More carefully controlled studies are needed before a special degree of criminality can be attributed to discharged mental patients. Twenty-eight references are appended.