The Mental Health Parity and Addiction Equity Act (MHPAEA) evaluation study: Did parity differentially affect substance use disorder and mental health benefits offered by behavioral healthcare carve-out and carve-in plans?

Even if SUD benefits had been historically less generous than MH benefits, SUD financial requirements were already at parity with MH financial requirements by the time MHPAEA was passed, among Optum® plans. MHPAEA's SUD parity mandate reduced cost-sharing for detox services via copayments, but, for outpatient detox, the law simultaneously increased cost-sharing via coinsurance.