In the landmark decision, Tarasoff v. Regents of University of California, the California court established the duty of medical professionals who know a patient is dangerous to prevent that person from harming third parties. In Tarasoff, [Tarasoff v. Regents of Univ. of Cal., 551 P.2d 334 (Cal. 1976)] a patient told his psychologist that he planned to kill his girlfriend, Tatiana Tarasoff. The psychologist, who was a counselor at the University of California, believed the patient and notified the campus police. The campus police detained the patient, but let him go without a formal psychiatric evaluation. The psychologist was notified and did nothing further to stop the patient, who then killed Tarasoff. Tarasoff’s family sued, and the court found that there was a duty to try and stop such a patient, including, under some circumstances, a duty to warn the intended victim.

Tarasoff is a peculiar case because it is unclear whether warning the victim is really the correct result. The information is of limited value to the victim because in most big cities such a threat will not trigger police protection. The better result in Tarasoff would have been for the psychologist to have initiated the proper proceeding for an involuntary civil commitment, as specified in the state’s mental health code, rather than just calling the campus police. This would have been especially important after he learned that the campus police had released the patient. The advantage of properly invoking the mental health commitment procedures is that it does not violate the patient’s confidence by involving the potential victim. Had the patient been properly evaluated by a forensic psychologist or psychiatrist before being released, it is very unlikely that the courts would have found a further duty to warn the intended victim.

The courts have found that Tarasoff is limited to situations where the health care practitioner is convinced that the patient is dangerous to a specific individual. General threats to kill everyone at the high school probably do not trigger a Tarasoff duty; however, if the medical care practitioner suspects that the patient might attack the school, it would be better to act. Some states, such as Washington, have extended Tarasoff by passing laws requiring health care practitioners to report persons who are dangerous by reason of mental illness.

As with other reporting duties, a good faith report to the proper authorities should not subject the medical care practitioner to legal liability for invasion of the patient’s privacy and will generally fulfill the duty to warn. However, this does not mean just calling the police. The medical care practitioner should find out the procedures that their state law provides for reporting and confining a person who is a danger to self or others. This usually involves some kind of affidavit attesting to the diagnosis and its factual basis, as well as identifying information about the patient. When the process is completed appropriately, the patient will be picked up and evaluated by a mental health expert, usually over a two- or three-day period. Only if this process fails, or is unavailable, should the medical care practitioner start warning third parties.