Challenging Prior Authorization as an MHPAEA Parity Violation

What makes prior authorization a non-quantitative treatment limitation?

The Mental Health Parity and Addiction Equity Act distinguishes between two types of treatment limitations. Quantitative treatment limitations are numerical caps — visit limits, day limits, dollar maximums. Non-quantitative treatment limitations (NQTLs) are everything else: clinical criteria, prior authorization requirements, network composition rules, step therapy protocols, and concurrent review standards.

Prior authorization is the quintessential NQTL. It does not limit the number of sessions allowed; it controls whether the plan will pay for any session at all unless a clinician first satisfies an administrative gate. Under 29 CFR § 2590.712(c)(4), any NQTL applied to mental health or substance use disorder (MH/SUD) benefits must be comparable to, and applied no more stringently than, NQTLs applied to substantially all medical/surgical benefits in the same classification.

The standard has two independent tests. The as-written test asks whether the plan's written policies impose PA requirements on behavioral health that are absent from comparable medical/surgical benefits. The in-operation test — added explicitly by the CAA 2021 statutory amendments and codified in the 2013 regulations — asks whether PA is actually applied more stringently in practice, regardless of what the plan documents say. Both tests must be satisfied; a plan that has parity on paper but applies PA inconsistently in claims processing fails the in-operation test.

The typical violation pattern looks like this: a plan covers outpatient specialist visits (cardiology, orthopedics, dermatology) with no prior authorization requirement. The same plan requires prior authorization for outpatient psychotherapy beginning at session one. Because the plan is applying a PA requirement to behavioral health that it does not apply to a comparable medical/surgical benefit in the outpatient classification, that asymmetry is a parity violation on its face.

What the 2025 enforcement data shows

The 2025 MHPAEA Report to Congress, released in early 2026 and covering DOL and CMS enforcement through July 31, 2025, documented a significant increase in both DOL and CMS enforcement activity compared to prior reporting periods. Both agencies issued more final determination letters — formal citations of parity violations — than in any previous cycle. CMS specifically noted that it issued “far more insufficiency letters,” meaning plans that submitted comparative analyses were frequently found to have omitted required elements, and many plans submitted nothing at all.

Prior authorization requirements dominated the NQTL categories cited. The following table summarizes the PA-related violations most commonly identified across enforcement actions reported in the 2025 cycle:

The last row in that table matters as much as the others. Failing to produce a comparative analysis when demanded is itself a federal violation under CAA 2021 § 203 — separate from whether the underlying PA requirement actually passes the parity test. When both the substantive violation and the disclosure failure are present, you have two independent bases for escalation.

Building the parity challenge: identifying your comparator

The parity argument lives or dies on the comparator. You need to identify a specific medical/surgical benefit in the same classification that the plan covers without the PA requirement — or with a materially lighter PA burden — that is analogous to the behavioral health service being denied.

For outpatient psychotherapy, the strongest comparators are services the plan covers in the same outpatient, in-network classification: ongoing specialist management visits, physical therapy sessions, or occupational therapy. The plan's summary plan description (SPD) and benefits guide are the starting point — request them in writing if you don't have them. Most plans make them available online or must produce them within 30 days of a written request under ERISA.

Once you have the comparator, the challenge is straightforward. Here is the step-by-step approach to building the parity argument for a CO-197 or OA-23 denial:

1. Identify the denial basis. CO-197 means prior authorization was absent or exceeded. OA-23 means the plan required authorization from another payer. Note the exact service denied (CPT code), the date of service, and the plan type (ERISA self-funded, fully-insured, or Medicaid managed care).
2. Pull the plan's PA schedule. Most SPDs or benefits guides include a list of services requiring prior authorization. Look specifically for whether comparable outpatient medical/surgical services — physical therapy, occupational therapy, specialist management — appear on the same PA list. If they don't, you have an as-written violation.
3. State the comparator explicitly. Your appeal letter must name the specific medical/surgical service the plan covers without PA (or with lighter PA). Vague parity claims — “mental health is treated worse than medical care” — rarely succeed. Specific comparator claims — “the plan covers ongoing physical therapy management without PA but requires PA for equivalent psychotherapy sessions” — put the plan in the position of either acknowledging the disparity or producing a comparative analysis to explain it.
4. Send the CAA 2021 § 203 demand simultaneously. Do not wait for the internal appeal to be denied before requesting the comparative analysis. Send both on the same day. The analysis can arrive while the appeal is still in the review window and strengthen your second-level arguments if needed.
5. Document everything with timestamps. The appeal submission date, the comparative analysis request date, and any response or non-response all matter for the escalation timeline. Certified mail and portal submissions both generate the records you'll need.

The CAA 2021 § 203 demand: what to say and how to send it

The Consolidated Appropriations Act of 2021, § 203 — codified at 29 U.S.C. § 1185a(a)(8) — requires every group health plan and health insurance issuer to perform and document a written comparative analysis of any NQTL applied to MH/SUD benefits, and to make that analysis available upon request to participants, beneficiaries, and regulators. The disclosure duty is in the federal statute itself, not in any regulation. It was not affected by the May 2025 tri-agency statement pausing enforcement of the 2024 Final Rule's new provisions.

Use this language in the appeal letter, adapted to the specific denial:

Under § 203 of the Consolidated Appropriations Act of 2021, codified at 29 U.S.C. § 1185a(a)(8), this plan is required to perform and produce a written comparative analysis of any non-quantitative treatment limitation applied to mental health and substance use disorder benefits. The prior authorization requirement that resulted in denial code [CO-197 / OA-23] for [CPT code] on [date of service] is a non-quantitative treatment limitation subject to this requirement. I am requesting the written comparative analysis, including: (1) the specific medical/surgical benefit the plan identified as the comparator; (2) the evidentiary standards and factors used to design and apply the prior authorization requirement to mental health benefits; (3) those same standards and factors for the comparator medical/surgical benefit; and (4) the plan's written findings and conclusions on comparability. Please respond within 30 days. Failure to produce a defensible comparative analysis, or failure to respond, is itself a violation of CAA 2021 § 203 and will be escalated to the relevant state and federal regulators.

Send this as part of the appeal letter itself — not as a separate document — so it is part of the official administrative record. For fully-insured plans, address it to both the plan administrator and the insurance carrier. For ERISA self-funded plans, address it to the plan administrator. Retain the tracking number from the plan's portal submission or the certified mail receipt.

One note on timing: the 2024 MHPAEA Final Rule (29 CFR § 2590.712-1) codified specific timeframes for plan responses and fiduciary certification requirements. Those provisions are under federal non-enforcement following ERIC v. DOL and the May 2025 tri-agency statement. The 30-day response window in the paragraph above is based on the CAA 2021 disclosure requirement and standard ERISA claim-procedure timelines, both of which remain fully in force. Do not cite the 2024 Final Rule provisions in a 2026 appeal.

When the plan responds: reading the comparative analysis

Receiving a comparative analysis is a better outcome than silence — it gives you something to evaluate and challenge. The 2025 enforcement cycle found that plans consistently failed on three dimensions, each of which is an independent basis for the next escalation step.

The comparator is vague or absent. A legally sufficient analysis must name a specific medical/surgical benefit in the same plan classification that the plan evaluated side by side with the behavioral health benefit. Generic references to “outpatient medical services” or “comparable medical care” without a specific named service are not sufficient. If the analysis doesn't name a comparator, note that deficiency explicitly in your second-level appeal: “The comparative analysis provided does not identify the specific medical/surgical benefit evaluated as the comparator, which is required under CAA 2021 § 203.”

Only the written policy is analyzed. MHPAEA requires the analysis to address both how the NQTL is designed (as written) and how it is actually applied in claims processing (in operation). Many plans produce analyses that describe their written PA criteria without any operational data — no claim-processing statistics, no audit results, no documentation of how PA authorization rates differ between behavioral health and the comparator. An analysis that omits the operational component fails the statutory test.

Assertion without data. The 2025 enforcement cycle identified plans concluding that PA requirements were comparable without citing any supporting evidence — no clinical-criteria review records, no utilization management audit results, no vendor analysis. If the plan asserts parity without data, the assertion is not a comparative analysis; it is a conclusion dressed up to look like one.

Any one of these deficiencies gives you the following argument for the second-level internal appeal or external review: “The plan's comparative analysis fails [name the specific requirement] as required by CAA 2021 § 203. The analysis therefore does not demonstrate that the prior authorization requirement applied to [service] is comparable to the PA burden applied to the named comparator, and the denial should be overturned on parity grounds.”

Escalation paths when the plan stalls

When the first-level appeal doesn't overturn the denial, pursue all three of the following escalation paths simultaneously rather than sequentially — they run in parallel and none of them closes the others.

External review through the state IRO process. For most denials on medical necessity or benefit-exclusion grounds, federal and state law guarantees access to an independent external review by a clinical reviewer with no relationship to the plan. The IRO's decision is binding on the plan. Request external review immediately after the first internal appeal is denied — most plans process second-level internal appeals slowly, and you lose nothing by initiating external review at the same time. Bring the parity argument and the comparative analysis demand into the external review record.

State Department of Insurance complaint (fully-insured plans). If the patient's plan is fully-insured — meaning it is sold and regulated by a state insurance commissioner, not self-funded by an employer — the state DOI has direct enforcement authority over MHPAEA parity violations. A written complaint citing the specific PA disparity and the plan's failure to produce a comparative analysis often prompts a response from the plan within days. State-by-state appeal guides include the relevant DOI contact and complaint process for all 50 states.

DOL EBSA complaint (ERISA self-funded plans). For self-funded employer plans, the DOL's Employee Benefits Security Administration receives complaints at askebsa.dol.gov. EBSA does not adjudicate individual claims, but it does pursue patterns of parity violations. The 2025 Report to Congress confirmed that EBSA actively follows up on documented comparative-analysis failures — filing a complaint creates a record that matters.

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