Changes in Access to Substance Use Disorder Treatment Associated with the 2008 U.S. Parity Law.
Level 3 - non-randomized controlled study
Quasi-experimental difference-in-differences analysis of repeated cross-sectional survey data (by design analogy)
What was done
Researchers conducted a secondary difference-in-differences analysis using repeated cross-sectional data from the National Survey on Drug Use and Health (2006–2014). They evaluated adults aged 18–64 meeting criteria for substance use disorder (SUD) treatment need, comparing outcomes among individuals with group-based private insurance (GBPI) to those with individual-based private insurance (IBPI) before (2006–2009) and after (2011–2014) implementation of the 2008 Mental Health Parity and Addiction Equity Act (MHPAEA).
What was found
Among 32,605 adults with SUD (weighted N = 16,108,465), 17,065 held GBPI. Adjusted past-year SUD treatment rates among GBPI enrollees remained low and showed no significant change after MHPAEA implementation (6.4% pre-parity vs. 7.0% post-parity; adjusted difference: +0.5 percentage points, 95% CI: -1.1 to 2.2, p = 0.514). The difference-in-differences estimate comparing GBPI to IBPI was not statistically significant (+3.1 percentage points, 95% CI: -3.8 to 10.0, p = 0.380). Perceived unmet SUD treatment need was unchanged (3.9% pre vs. 3.9% post; +0.1 percentage points, 95% CI: -1.0 to 1.1, p = 0.895). Among GBPI enrollees reporting unmet need, post-MHPAEA barriers included ambivalence about treatment (66.8%), accessibility (22.8%), stigma (19.1%), and cost (14.9%). Only half of GBPI enrollees knew their insurance covered SUD care, while roughly 40% were unaware.
Why it matters
Federal insurance parity mandates did not translate into increased SUD treatment utilization or lower perceived unmet need among privately insured adults. Expanding treatment uptake requires addressing non-financial barriers, including low coverage awareness, stigma, ambivalence, and provider availability.
Limits
The study relied entirely on self-reported survey data, could not identify specific insurance plans that were exempt from MHPAEA requirements, and lacked state-level identifiers to control for pre-existing state parity laws.
Cited by
- supports Federal mental health and addiction parity legislation passed in the United States in 2008 requiring commercial insurance plans to cover mental health and addiction benefits at comparable levels to medical and surgical benefits.