Mental Health Parity Enforcement: Why the Law Exists and Why It Is Not Working

The Mental Health Parity and Addiction Equity Act of 2008 established one of the clearest legal mandates in health insurance law: mental health and substance use disorder benefits must be no more restrictive than medical and surgical benefits in health insurance plans. After fifteen years of the law being in effect, extensive documentation shows that parity violations are widespread, that the populations the law was designed to protect continue to face discriminatory coverage, and that enforcement mechanisms have proven inadequate to the task. The parity law's requirements operate at two levels. Quantitative treatment limitations, including day and visit limits on covered services, must not be more restrictive for mental health and substance use care than for medical and surgical care. Non-quantitative treatment limitations, including prior authorization requirements, provider network standards, reimbursement rates, and step therapy protocols, must also not be more restrictive. The NQTL requirements are more complex to evaluate because they involve comparative analysis of how insurers apply limitations across different benefit categories. Enforcement authority for the parity law is divided across federal agencies. The Department of Labor enforces the law for employer-sponsored health plans. The Department of Health and Human Services enforces it for plans regulated under the Affordable Care Act. State insurance departments enforce it for plans regulated at the state level. This fragmented enforcement structure has contributed to inconsistent implementation and limited accountability. A 2022 report from the Department of Labor found widespread parity violations in a review of major insurance plans. The report documented that insurers applied more stringent prior authorization requirements, narrower provider networks, more frequent utilization management, and lower reimbursement rates for mental health and substance use services than for comparable medical services. These findings were consistent with what mental health advocates and patients had been reporting for years. Prior authorization is among the most commonly cited barriers to mental health care access, requiring patients to obtain insurer approval before receiving services that physicians and patients believe are medically necessary. Research on prior authorization in mental health found that approval rates for mental health services are lower than for medical services, and that the process imposes administrative burdens on providers and patients that reduce care access even when services are ultimately approved. Provider network adequacy is a structural parity violation that affects access by limiting the pool of in-network providers available for mental health and substance use services. When reimbursement rates for mental health providers are set too low to attract adequate providers into the network, the result is that patients either pay out-of-network rates or go without care, even when they nominally have mental health coverage. Research documents that mental health provider networks are significantly narrower than medical networks in many insurance plans. Enforcement actions under the parity law have been limited in number and scope. The complexity of conducting the comparative analyses needed to establish parity violations, the limited resources of enforcement agencies relative to the number of plans subject to the law, and the technical legal challenges of building enforceable cases have all contributed to the gap between the law's requirements and its practical implementation. Strengthening of parity law enforcement has been pursued through regulatory guidance, legislation, and advocacy. The Consolidated Appropriations Act of 2021 included provisions strengthening parity requirements and requiring plans to conduct and document comparative analyses of their mental health and medical benefit limitations. The Biden administration issued guidance on how these analyses should be conducted and what insurers must demonstrate. Whether these strengthened requirements will produce better enforcement outcomes remains to be seen as implementation develops. Patient advocates, mental health providers, and state attorneys general have pursued parity enforcement through litigation and complaint processes, some of which have produced significant outcomes. The landmark Wit v. United Behavioral Health decision, in which a federal court found that UBH had applied coverage criteria that were more restrictive than generally accepted standards of care, illustrates the potential for legal action to enforce parity requirements. The case went through multiple appeals with evolving outcomes that illustrate the legal complexity of parity enforcement.