As a special case of posttraumatic stress disorder, BWS rests on a combination of two theories, namely, the "cycle of violence" and "learned helplessness." These theories describe a pattern of behavior that women who are abused by their partners frequently manifest. This syndrome has a cycle of behavior that consists of three stages: the tension-building stage, the acute-battering stage, and the contrition stage. Symptoms associated with the syndrome are low self-esteem, self-blame, anxiety, depression, fear, suspiciousness, and loss of belief in the possibility of change. These psychological traits prevent women from leaving their abusers. In the 1990 case of Regina (R.) v. Lavallee, the Supreme Court of Canada first granted Canadian women the opportunity to rely on BWS evidence through expert testimony as part of a self-defense claim in the killing of their abusers. Following this precedent-setting decision, Canadian courts have admitted this kind of expert testimony in trials of battered women. Typically, BWS is not a legal defense in itself in Canada; rather it is a psychiatric explanation of the mental state of an abused woman that can be relevant to understanding a battered woman's state of mind. More recently social science theorists have argued that BWS is compounded by the lack of protection afforded to abused women by public institutions such as the courts, police, and medical professionals. The state of extreme vulnerability and helplessness increases the sense of desperation felt by women suffering from BWS. BWS testimony has sparked controversy in Canadian legal circles regarding its underlying views of women, with some arguing that it portrays all battered women as weak, defenseless, and helpless, when in fact there are cases in which battered women do not fit the profile of the passive, submissive, helpless, and dependent stereotype of the battered woman. A broader perspective on battered women is warranted, according to many experts, one that would focus on control and the loss of liberty by battered women as part of larger problems of power and control within intimate relationships. Such a focus would encompass not only psychological states of battered women, but also financial dependency and the inadequacies of social and public safety institutions in addressing the plight of battered women. 46 references