Legal implications of premenstrual syndrome: a Canadian perspective.

A summary of the symptoms, prevalence and history of premenstrual syndrome (PMS) is presented. The legal implications of PMS, particularly its use as a defence in criminal prosecutions and as an implicit factor in specific offences, are discussed by means of an analysis of Canadian legal cases, with reference to those in England and the United States. The authors offer suggestions on how physicians can make use of PMS in a courtroom more reliable. They conclude that PMS is unlikely to become a substantive criminal defence until the medical community more fully recognizes its significance. Although the role of PMS as a mitigating factor in sentencing may be illogical, the courts now recognize the syndrome in a legally and practically important manner.