Doing Their Duty: An Empirical Analysis of the Unintended Effect of Tarasoff v. Regents on Homicidal Activity

The seminal ruling of Tarasoff v. Board of Regents of the Universities of California enacted a duty that required mental health providers to warn potential victims of any real threat to life made by a patient. Many have theorized that this required breach of confidentiality may have adverse effects on effective psychological treatment—but the issue remains unaddressed empirically. Because of the presence of duty-to-warn laws, patients might forgo mental health treatment that would prevent violence. Using a fixed-effects model and exploiting the variation in the timing and style of duty-to-warn laws across states, I find that mandatory duty-to-warn laws cause an increase in the homicide rate of .4, or 5 percent. These results are robust to model specifications and falsification tests and help to clarify the true effect of state duty-to-warn laws.