Mental Health Parity Appeals: How Providers Use MHPAEA

What is mental health parity? Mental health parity is the federal requirement, set by MHPAEA (29 U.S.C. § 1185a) and its regulations at 29 CFR 2590.712 and 45 CFR 146.136, that financial requirements and treatment limitations on mental health and substance use disorder benefits be no more restrictive than those on medical/surgical benefits.

Undeny's Take

Treat parity as a demand for evidence, not a trump card. Most therapy denials are still won on the facts: the notes, the authorization, the right code. What parity adds is a shift in who has to show their work. Once you ask for the medical necessity criteria and the plan's comparative analysis, the plan has to explain why its rule for a 90837 session is no stricter than its rule for a comparable medical visit. That is a harder question for a plan to answer than whether one progress note was detailed enough. Use it when the denial comes from how the plan manages care: prior authorization, concurrent review after a set number of sessions, medical necessity criteria, a visit cap or a treatment exclusion. Leave it out of coding and eligibility denials, where it only adds noise. Keep it to one paragraph inside a normal appeal, and don't cite the 2024 rule: its new provisions are not being enforced.

Does Mental Health Parity Apply to This Plan?

Check the coverage type before you write a word about parity. The law reaches most commercial and Medicaid managed care coverage, but not Medicare.

Coverage	Parity applies?	Where the rule lives
Employer plan, more than 50 employees	Yes, if the plan covers mental health or substance use care at all	ERISA § 712 and 29 CFR 2590.712; PHSA § 2726 and 45 CFR 146.136
Insured small-group or individual plan	Yes, through the essential health benefits rules	45 CFR 156.115(a)(4)
Medicaid managed care (MCO, PIHP, PAHP)	Yes, under Medicaid's own parity rules	42 CFR 438.910 and 438.915
Original Medicare or Medicare Advantage	No	Appeal on Medicare's coverage rules instead

Two limits are worth knowing. The federal rule exempts group health plans of small employers, defined as an average of 2 to 50 employees, although insured small-group coverage still has to meet parity through the essential health benefits requirement. And MHPAEA does not force a large employer plan to cover mental health care at all: the statute says nothing in it requires a group health plan "to provide any mental health or substance use disorder benefits." Parity governs how a plan covers those benefits once it offers them.

What Counts as a Treatment Limitation Under MHPAEA

Parity compares mental health and medical/surgical benefits within the same classification. Commercial plans use six: inpatient in-network, inpatient out-of-network, outpatient in-network, outpatient out-of-network, emergency care and prescription drugs. Plans may split outpatient benefits into office visits and all other outpatient services. Medicaid managed care uses four: inpatient, outpatient, emergency care and prescription drugs. Most therapy and ABA claims fall in an outpatient classification.

Within a classification, three kinds of limits are tested:

• Financial requirements: copays, coinsurance, deductibles and out-of-pocket maximums.
• Quantitative treatment limitations (QTLs): numeric caps such as annual visit or day limits. A type of QTL that does not apply to at least two-thirds of medical/surgical benefits in the classification cannot be applied to mental health benefits there at all, and where it does qualify, the mental health limit cannot be stricter than the level that applies to more than half of those medical/surgical benefits.
• Nonquantitative treatment limitations (NQTLs): rules that limit care without a number.

The NQTL test in the regulation

A plan may not impose an NQTL on mental health benefits unless, "as written and in operation," the processes, strategies, evidentiary standards or other factors behind it "are comparable to, and are applied no more stringently than," those used for medical/surgical benefits in the classification. The regulations list examples, including medical management standards based on medical necessity or on whether treatment is experimental, formulary design, network admission standards including reimbursement rates, methods for setting usual and customary charges, fail-first or step therapy, exclusions for failing to complete a course of treatment, and restrictions based on geography, facility type or provider specialty.

Denials Where a Parity Argument Fits

• Prior authorization for routine outpatient therapy (CO-197). Ask whether the plan requires prior authorization for comparable outpatient medical visits in the same classification.
• Medical necessity (CO-50). Request the exact criteria applied. Pair the parity request with a strong letter of medical necessity.
• Concurrent review or frequency limits (CO-151). Ask what triggers review for medical/surgical outpatient care and whether the same trigger applies after a set number of psychotherapy sessions.
• Visit caps (CO-119). A session cap is a QTL; ask whether a visit limit of that type applies to at least two-thirds of medical/surgical outpatient benefits.
• Treatment exclusions. A blanket exclusion or hours cap on a service such as ABA (97153) is a scope limit worth testing against how the plan treats comparable medical services.

Parity does not help with missing information, modifier errors, timely filing or patient responsibility amounts. Fix those on their own terms.

How to Write the Parity Section of an Appeal

1. Confirm the coverage type using the table above, and skip parity entirely for Original Medicare and Medicare Advantage.
2. Name the limitation that produced the denial (prior authorization, concurrent review, medical necessity criteria, a visit limit or an exclusion) and the classification, usually outpatient in-network or out-of-network.
3. Request the medical necessity criteria in writing. Plans must make them available "to any current or potential participant, beneficiary, or contracting provider upon request" under 29 CFR 2590.712(d)(1) and 45 CFR 146.136(d)(1); Medicaid managed care plans must do the same under 42 CFR 438.915(a).
4. Have the patient sign the plan's authorized representative designation if you will request plan documents on their behalf.
5. For an employer plan, request the documents relevant to the claim, which the ERISA claims rule at 29 CFR 2560.503-1 entitles the claimant to receive free of charge, and the plan's comparative analysis for the limitation.
6. Add one parity paragraph to the appeal, framed as a request for the plan to show compliance rather than an accusation.
7. File the appeal by the plan's deadline even if the documents have not arrived, and add them when they do.
8. If the denial stands, use the next level: external review for denials based on medical judgment, a complaint to the regulator, or for Medicaid, the enrollee's state fair hearing.

Sample parity paragraph

Because this claim is for mental health or substance use disorder services, we ask the plan to confirm its compliance with the Mental Health Parity and Addiction Equity Act (29 U.S.C. § 1185a; 29 CFR 2590.712; 45 CFR 146.136), to the extent the plan is subject to it. Any nonquantitative treatment limitation applied to this service, including prior authorization, concurrent review or medical necessity criteria, must be comparable to, and applied no more stringently than, the limitation applied to medical/surgical benefits in the same classification. Please provide the medical necessity criteria used in this determination (29 CFR 2590.712(d)(1)) and, on behalf of the member, the plan's comparative analysis for this limitation under ERISA § 712(a)(8). If the plan cannot show the limitation was applied comparably, we ask that the claim be reprocessed for payment.

The NQTL Comparative Analysis

The Consolidated Appropriations Act, 2021 added a requirement that group health plans and issuers covering both kinds of benefits "perform and document comparative analyses of the design and application of NQTLs" and make them available to regulators on request. The Department of Labor's FAQs Part 45 add that ERISA plans must also provide these analyses to participants and beneficiaries who ask. This is the document that should explain, limitation by limitation, why a plan's rule for therapy is no stricter than its rule for medical care. A plan that cannot produce one, or produces one that does not cover the limitation in your denial, has handed you a strong appeal point.

The 2024 Parity Rule: What Changed and What Didn't

In September 2024 the Departments of Labor, Health and Human Services and the Treasury finalized a rule adding new NQTL requirements, including data collection and a ban on discriminatory factors. An employer group sued in January 2025. On May 15, 2025 the Departments said they would not enforce the parts of the 2024 rule that are new relative to the 2013 rule, for failures before a final decision in that litigation plus 18 months, and that plans may continue to refer to the 2013 rule. In 2026 they signaled they would replace the 2024 rule through new rulemaking.

What still applies: the statute, the 2013 rule's comparable-and-no-more-stringent NQTL standard, the medical necessity criteria disclosure rule and the 2021 comparative analysis requirement. Build your appeal on those and leave the 2024-only provisions out. Some states have their own parity laws that go further, so check your state insurance code for fully insured plans.

Frequently Asked Questions

Does mental health parity apply to Medicare?

No. MHPAEA applies to group health plans, health insurance issuers and, through separate federal rules, Medicaid managed care plans. Original Medicare and Medicare Advantage are not subject to it, so a Medicare appeal should rest on Medicare's own coverage rules and documentation requirements.

Can a provider request the plan's medical necessity criteria?

Yes. The parity regulations require plans to make the medical necessity criteria for mental health and substance use disorder benefits available to any current or potential participant, beneficiary or contracting provider on request, under 29 CFR 2590.712(d)(1). Medicaid managed care plans have the same duty under 42 CFR 438.915(a).

What is an NQTL comparative analysis?

It is a written analysis, required since the Consolidated Appropriations Act, 2021, showing that each nonquantitative treatment limitation on mental health benefits, such as prior authorization, is comparable to and applied no more stringently than the same limitation on medical benefits. ERISA plans must provide it to participants and beneficiaries on request.

Is the 2024 mental health parity rule in effect?

It was finalized in September 2024, but in May 2025 the Departments said they would not enforce its new requirements while they reconsider the rule, and in 2026 they signaled plans to replace it. The 2013 rule and the 2021 comparative analysis requirement still apply.

Does parity mean a plan has to cover therapy?

Not for a large employer plan. MHPAEA does not require a group health plan to offer mental health or substance use disorder benefits, but if it does, the limits must meet parity. Individual and insured small-group plans must cover these services as essential health benefits.

Is a cap on therapy sessions allowed?

A session cap is a quantitative treatment limitation. It is allowed only if a visit limit of that type applies to at least two-thirds of medical/surgical benefits in the same classification, and the therapy cap is no stricter than the level that applies to more than half of them.

What if the plan won't send the criteria?

Record the date of your written request and the lack of response, cite both in the appeal, and keep going. Patients in private employer plans can contact the Department of Labor's Employee Benefits Security Administration, insured plans answer to the state insurance department, and Medicaid plans answer to the state Medicaid agency.

Informational only, not legal, medical, or billing advice. Parity rules are changing; verify against current federal guidance, your state's law and the plan documents before filing.

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