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You have probably lived this: your plan covers a 15-minute doctor visit for a sore knee with a $25 copay, but therapy for anxiety requires prior authorization, costs $80 a session, and the only in-network therapist is booking three months out. The Mental Health Parity and Addiction Equity Act, a federal law passed in 2008, says that gap is not supposed to exist. Here is what the law requires, where it falls short in practice, and what to do when your plan does not follow it.
What the parity law says
The parity law applies to most employer-sponsored group health plans and to individual market plans. Its core rule is simple: if a plan covers mental health or substance use disorder benefits, it cannot impose financial requirements or treatment limitations on those benefits that are more restrictive than the ones it applies to medical and surgical benefits.
That covers three categories. Financial requirements include deductibles, copays, and coinsurance. Quantitative treatment limitations include things like visit limits or day limits. Nonquantitative treatment limitations (NQTLs) are the trickiest category: prior authorization rules, step therapy, network admission standards, and medical necessity criteria. A plan cannot make you jump through tougher hoops to get therapy approved than it makes you jump through to get physical therapy approved.
The 2024 final rule and where it stands now
In September 2024, the Departments of Labor, Health and Human Services, and Treasury issued a final rule meant to strengthen parity enforcement. It required plans to collect and evaluate data showing whether their NQTLs actually produced equal access in practice, not just on paper, with some provisions applying to plan years starting in 2025 and the data requirements applying to plan years starting in 2026.
That rule ran into trouble. An employer group sued to block it, and in May 2025 the federal agencies announced they would not enforce the provisions of the 2024 rule that go beyond the 2013 regulations while the litigation plays out and the administration reconsiders the rule. A new final rule is expected by the end of 2026.
None of that removed the underlying law. In September 2026, the Department of Labor issued enforcement guidance identifying three priority areas: blanket exclusions of mental health or substance use treatment, medical necessity and prior authorization processes, and network adequacy. The statutory requirements, including the comparative analyses Congress added in 2021, remain in effect. The law still binds your plan even while the newest rule is on ice.
Where parity breaks down in real life
Network adequacy is the biggest gap. A plan can have identical copays for therapy and primary care on paper while maintaining a behavioral health network so thin that nobody can actually get an appointment. Low reimbursement rates push therapists out of networks, and the result is a directory full of names that do not answer the phone.
Prior authorization is the second gap. Plans often require approval before covering intensive treatments like residential care or repeated transcranial magnetic stimulation, using medical necessity standards that are stricter in practice than the ones applied to comparable medical procedures. Denials for “not medically necessary” are the most common parity complaint.
Blanket exclusions are the third. Some plans exclude entire categories of care, such as treatment for certain eating disorders or autism-related therapies, while covering analogous medical treatments. These are the cases regulators are most aggressively pursuing.
What to do when your claim is denied
Start by asking for the denial in writing with the specific reason and the medical necessity criteria the plan used. Plans are required to provide this. Then file an internal appeal with the plan. You have the right to an external review by an independent third party if the internal appeal fails, and external reviewers overturn a meaningful share of denials.
If you suspect a parity violation, compare the requirement imposed on your mental health claim with what the plan requires for medical claims. Did the plan require prior authorization for six therapy sessions but not for six physical therapy sessions? That comparison is the heart of a parity complaint. You can file a complaint with the Department of Labor’s Employee Benefits Security Administration if you have employer coverage, or with your state insurance department for individual market plans.
Keep records of everything: dates you called, names of representatives, what was denied and why. Parity cases are won on documentation.
What parity does not do
The law does not require plans to cover mental health care at all, with one big exception: ACA marketplace plans and Medicaid expansion plans must cover mental health and substance use treatment as essential health benefits. For large employer plans, the parity rule only applies if the plan chooses to offer the benefit. Most do, but a plan that covers no mental health care is not violating parity.
The law also does not guarantee that care will be affordable or available. It guarantees equal rules, not equal outcomes. A $40 copay for therapy that matches the $40 copay for a specialist visit satisfies the financial part of parity even if you cannot find a therapist. Closing that gap is what the data requirements in the contested 2024 rule were trying to do, and it is why enforcement is now focused on network adequacy.
If you are shopping for a plan, check the behavioral health network before you enroll, not after. Call three therapists in the directory and ask if they are taking new patients with your plan. That 15-minute test tells you more about real access than any parity disclosure. Our open enrollment checklist includes this step alongside the others worth doing every year.
