Presentation (CTI)

OBJECTIVES: To evaluate the impact of a 2016 behavioral health parity reform on ambulatory specialty mental health care utilization among beneficiaries of TRICARE, the civilian-purchased health insurance program of the U.S. Military Health System serving military personnel, retirees, and their families. The reform eliminated quantitative and non-quantitative treatment limits for mental health services and streamlined civilian provider contracting to enhance provider availability.
METHODS: We analyzed 2011-2023 U.S. Medical Expenditure Panel Survey data using difference-in-differences-in-differences (DDD) and two-part (hurdle) models. The sample included adults (aged 18-64) in TRICARE (treatment) or private insurance (control). To isolate the reform's targeted impact, the DDD exploited differential treatment intensity: we contrasted beneficiaries with serious mental illness (SMI), the high-need group historically constrained by coverage limits, against those without SMI. The non-SMI cohort served as a within-system control to absorb concurrent system-wide shocks. Outcomes included annual specialty mental health and psychotherapy visits, expressed as full marginal effects (FMEs).
RESULTS: Event-study analyses confirmed parallel pre-parity reform trends and revealed no anticipatory behavior. While TRICARE beneficiaries without SMI experienced significant utilization declines (all mental health visits FME= -0.37, p<0.001; psychotherapy FME= -0.27, p<0.001), DDD estimates isolating the SMI-specific effect were consistently positive (e.g., +1.14 total visits). This indicates that the reform disproportionately buffered the high-need SMI cohort against broader system-wide declines, though the DDD estimates did not reach conventional statistical significance.
CONCLUSIONS: Parity reform did not significantly increase specialty mental health utilization among high-need TRICARE beneficiaries. However, the post-reform utilization decline among low-need beneficiaries may suggest a supply-side crowding-out effect. The findings may also indicate that benefit expansions alone cannot overcome persistent nationwide provider shortages that constrain system capacity, nor the elevated stigma that suppresses effective demand in military-connected populations. Sustained access gains require concurrent supply-side investments to strengthen the civilian provider network alongside targeted efforts to reduce military-specific stigma.