Impact of State-Level Behavioral Health Reforms on Mental Health and Alcohol Use: A Quasi-Experimental Study Using BRFSS Data (2012–2023)

Introduction Understanding the population-level effects of state-level behavioural health reforms is vital in addressing the rising burden of mental health disorders and substance use. Objective To assess the impact of selected state-level policy interventions on mental health and alcohol use outcomes using a quasi-experimental difference-in-differences (DiD) approach with nationally representative data. Methods We analysed Behavioural Risk Factor Surveillance System (BRFSS) data from 2012–2023, comparing four intervention states (California, Massachusetts, Nevada, and Vermont) to other U.S. states. Key outcomes included self-reported mentally unhealthy days and any alcohol use in the past 30 days. DiD linear regression models were applied, including extended analyses covering the COVID-19 pandemic years. Results Post-intervention, treatment states experienced a statistically significant increase in mentally unhealthy days (β = 1.45; 95% CI: 0.98–1.91; p < 0.001), which attenuated and became non-significant in the extended period. Alcohol use did not change significantly in the short term but declined modestly in treatment states over the extended analysis (β = -0.0075; 95% CI: -0.0129 to -0.0021; p = 0.006). Conclusions State-level reforms may have short-term effects on mental health burden and longer-term benefits for reducing alcohol use. These findings highlight the need for sustained policy evaluation and tailored implementation strategies amid broader societal disruptions like the COVID-19 pandemic.