Effects of giving psychologists prescriptive authority: Evidence from a natural experiment in the United States

Background: Suicide is the tenth leading cause of death in the U.S. Six states have granted psychologists prescriptive authority to address shortages in the provision of behavioral and mental health care services to increase provider access to pharmacological interventions using psychotropic medications.

Methods: This study estimates the impact of expanding scope of practice for specifically trained psychologists to include pharmacological interventions on mortality by self-inflicted injury in the U.S. by using the implementation of prescriptive authority for psychologists in New Mexico and Louisiana as a natural experiment using a staggered different-in-difference estimation. Additional robustness tests are conducted to identify heterogenous treatment effects, observe sensitivity of our results for Medicaid expansion, and to compare other forms of mortality that should not have been affected by psychologist prescriptive authority.

Results: Mortality resulting from self-inflicted injury decreased by 5 to 7 percentage points in New Mexico and Louisiana following prescriptive authority expansions for psychologists. The effect is statistically significant for males, white populations, individuals who are married or single, and for people between the ages of 35 and 55.

Conclusions: In the U.S., expanding scope of practice for specifically trained psychologists to include prescriptive authority may help address poor mental health care outcomes, such as suicides. Similar policy expansions may be useful for other countries where referral from a psychologist and prescription assignment from a psychiatrist are separated.