The practice of medicine is increasingly subject to external review and legislation.  Both have a significant impact on psychiatry in terms of  risk assessment and the duty to warn or protect third parties (1–4). Tarasoff v. the Regents of the University of California (1974),  the seminal American case, not only brought the issue to the forefront but also began the ongoing process of attempting to clarify the clinician’s obligation to protect society from potentially dangerous patients (5).

Since Tarasoff, there have been numerous related cases in the US and several pertinent cases in Canada (3,4,6,7–9). In response to the growing acceptance of a duty to warn and protect, many of the U.S. states have enacted legislation to define that duty or responsibility in law (10). At the same time, professional organizations have attempted to define the responsibilities of their membership in this regard, as the obligations may be unclear, and the act of warning or protecting may breach the time-honoured principle of confidentiality (11–13).

The duty to warn and protect is a relatively new concept and is a departure from traditional psychiatric practice. This so-called duty is to a large degree defined by legislation and case law.

Manuscript received and accepted November 2000.
¹Assistant Professor, Department of Psychiatry and Behavioural Neurosciences, McMaster University, Hamilton, Ontario; Clinical Director and Forensic Psychiatrist, Hamilton Psychiatric Hospital, Hamilton, Ontario.
²Assistant Clinical Professor, Department of Psychiatry and Behavioural Neurosciences, McMaster University, Hamilton, Ontario; Assistant Professor, Department of Psychiatry, University of Toronto, Toronto, Ontario.
³Partner, Paterson MacDougall, Toronto, Ontario; Assistant Clinical Professor, Department of Psychiatry and Behavioural Neurosciences, McMaster University, Hamilton, Ontario.
Address for correspondence: Dr G Chaimowitz, Department of Psychiatry and Behavioural Neurosciences, McMaster University, 100 West 5th Street, PO Box 585, Hamilton, ON L8N 3K7
e-mail: chaimow@mcmaster.ca

Because this is an ongoing process, the exact nature of this duty remains difficult to define at any one time. What has begun to happen, however, is the growth of a body of literature on the “Duty to Warn and Protect”; a body of literature that becomes obsolete as new legislation and case law emerges. We describe the evolving concept of duty to protect and the often competing obligation of maintaining patient–physician confidentiality.

This paper provides an analysis of recent pertinent Canadian case law. The overall impact on the practice of psychiatry is discussed.

Duties to Warn and Protect

The issue of duties to protect or warn third parties at risk of violence from patients was first highlighted in the now well-known Tarasoff case (5,14).  Unfortunately, in the subsequent zeal to discuss and describe and promote the outcome of this particular case, the original case, Tarasoff I, with its Duty to Warn, is often the only one quoted (5,15). In actual fact, it is Tarasoff II that uniquely distinguishes the ideas of the Duty to Warn and the Duty to Protect (14).

In Tarasoff, Mr Prosengiit Poddar told his treating psychologist that he planned to kill his former girlfriend, Ms Tatiania Tarasoff. In response, the clinician provided both oral and written warnings to the campus police (a fact not known by many clinicians), who interviewed Mr Poddar and subsequently released him. Mr Poddar later insinuated himself with Ms Tarasoff’s family and then killed her. Her parents initiated a lawsuit.

The case was eventually heard in the California Supreme Court, which, in Tarasoff I 1974, reversed the Appellate decision that there was no cause of action. The Supreme Court