OIG Finds Medicaid Plans Denying Mental Health Claims at Higher Rates: What Psychiatry Practices Need to Know

What Did the OIG Medicaid Mental Health Parity Audits Find?

As of August 2026, the HHS Office of Inspector General released three state-specific audit reports finding that Medicaid managed care organizations in Kansas, New York, and Arizona are denying prior authorization requests for mental health and substance use disorder services at higher rates than for medical and surgical services, in violation of federal parity requirements under the Mental Health Parity and Addiction Equity Act. For psychiatry practices that bill Medicaid MCOs, these findings confirm that parity failures are creating measurable revenue loss through elevated denial rates on psychotherapy, psychiatric evaluation, and medication management claims.

• MCOs are denying MH/SUD claims at higher rates. In New York, selected MCOs’ denial rates for behavioral health prior authorizations exceeded the state’s threshold and were not comparable to denial rates for medical and surgical services in the same benefit classification.
• States are not enforcing compliance. In Kansas, none of the three audited MCOs completed a parity analysis during the audit period, and the state did not request one. Oversight gaps like these persist more than six years after the October 2017 compliance deadline.
• Prior authorization is the enforcement gap. All three audits focused specifically on prior authorization, the mechanism that most directly delays or blocks access to psychiatric care and triggers claim denials for practices.

What the OIG Reports Revealed

On August 10 and August 13, 2026, the HHS Office of Inspector General published three audit reports examining whether Kansas, New York, and Arizona ensured that their Medicaid managed care organizations complied with mental health and substance use disorder parity requirements related to prior authorization. These reports are part of a broader OIG audit series that began after a prior review found that CMS did not ensure eight selected states complied with Medicaid managed care parity requirements. The eight states in the original review were Arizona, Illinois, Kansas, Mississippi, New Jersey, New York, South Carolina, and Texas.

The Kansas report (A-07-24-02842) found that none of the three selected MCOs completed a parity analysis during calendar year 2023. The state government did not request a complete analysis from any MCO, did not provide guidance on parity compliance, and did not have oversight systems in place to monitor whether MCOs were treating behavioral health prior authorizations the same as medical and surgical authorizations. One MCO in Kansas was found to deny 34 percent of prior authorization requests for out-of-network outpatient behavioral health services compared to 22 percent for medical and surgical services.

The New York report (A-02-24-01011) found that although New York implemented a parity compliance program, the three selected MCOs’ analyses comparing denial rates were not sufficiently supported, and denial rates for behavioral health services exceeded the state’s established threshold. These noncompliance issues persisted more than six years after the October 2017 federal compliance deadline.

The Arizona report (OAS-24-09-002) found that only one of three MCOs complied with the state requirement to perform an annual parity analysis. The other two MCOs did not perform an analysis and could not demonstrate compliance with parity requirements for behavioral health prior authorization.

Which Psychiatry Practices Are Affected?

Any psychiatry practice that bills Medicaid managed care organizations for outpatient services is affected by these findings. The audits focused on prior authorization, which is the gatekeeper for reimbursement on psychotherapy, psychiatric evaluations, medication management, and crisis services. If your practice has experienced prior authorization denials on codes like 90833, 90834, 90837, or psychiatric evaluation codes 90791 and 90792 from a Medicaid MCO, the parity violation pattern identified in these audits may be contributing to those denials.

The impact scales with Medicaid payer mix. Psychiatric practices in states with high Medicaid managed care enrollment commonly report 30 to 50 percent or more of their payer mix in Medicaid. For those practices, elevated denial rates on behavioral health prior authorizations translate directly into delayed revenue, increased administrative burden, and lost income on services already delivered.

Providers often come to us after experiencing a pattern of denials from a single Medicaid MCO that does not match their experience with commercial payers or Medicare. These OIG findings explain why: the MCO may be applying prior authorization requirements more restrictively to behavioral health services than to medical and surgical services, which is exactly the disparity that parity law prohibits.

Why Parity Enforcement Has Lagged

The Mental Health Parity and Addiction Equity Act requires that health plans, including Medicaid MCOs, apply financial requirements and treatment limitations to mental health and substance use disorder benefits no more restrictively than to medical and surgical benefits. The compliance deadline for Medicaid managed care was October 2017. Nearly nine years later, the OIG audit findings show that basic compliance mechanisms, such as conducting an annual parity analysis comparing behavioral health and medical denial rates, are still not in place in multiple states.

Several factors explain why enforcement has been slow. States delegate behavioral health coverage to MCOs through managed care contracts, but many state contracts do not include specific parity compliance requirements or monitoring mechanisms. CMS issued regulations and guidance, but the 2024 final MHPAEA rule was paused for revision in March 2026 by the current administration, creating ambiguity about which compliance standards apply. The Department of Labor’s 2025 MHPAEA report to Congress confirmed that all 210 health plan analyses reviewed failed initial compliance. Despite these failures, enforcement has been limited because the responsible agencies have not had consistent resources or regulatory clarity to hold MCOs accountable.

For psychiatry practices, the practical result is that parity protections exist on paper but are not consistently enforced at the MCO level. This creates a billing environment where behavioral health claims face prior authorization barriers that equivalent medical claims do not. If your practice bills Medicaid and has not reviewed your MCO’s parity compliance, our Medicaid guide for behavioral health practices covers the foundational requirements.

What Does a Parity Violation Look Like on a Psychiatry Claim?

A parity violation in prior authorization shows up as a denial or delay that would not occur on a comparable medical or surgical claim. The OIG reports identified specific patterns that psychiatry billing teams should recognize.

The most direct indicator is a higher denial rate for behavioral health prior authorizations compared to medical and surgical authorizations in the same benefit classification. In Kansas, one MCO denied 34 percent of out-of-network outpatient behavioral health prior authorization requests while denying only 22 percent of medical and surgical requests. That 12-percentage-point gap is the measurable footprint of a parity violation.

Other patterns include requiring prior authorization for psychotherapy sessions when no comparable authorization is required for medical office visits of similar complexity, imposing visit frequency limits on therapy that do not apply to physical therapy or other outpatient services, and applying more stringent medical necessity criteria to psychiatric evaluations than to medical evaluations. Each of these is a nonquantitative treatment limitation that parity law requires to be applied comparably across behavioral health and medical services.

What to Do Now if You Bill Medicaid MCOs

The OIG reports do not create new requirements for providers, but they do create new leverage. Here is what a psychiatry practice should do in response.

• Pull your denial data by payer. Run a report from your practice management system or billing software showing prior authorization denial rates for behavioral health CPT codes compared to any medical or surgical codes your practice bills. If denial rates for behavioral health services are materially higher from a specific Medicaid MCO, document the disparity.
• Compare your MCO’s prior authorization requirements against medical and surgical equivalents. Review the MCO’s provider manual for the specific prior authorization requirements on psychotherapy, psychiatric evaluation, and medication management codes. Then check whether comparable outpatient medical services require the same level of authorization. If behavioral health services face more restrictive requirements, that is the basis for a parity inquiry.
• File a parity complaint with your state Medicaid agency. Every state has a process for providers to report potential parity violations. The OIG reports specifically recommended that states strengthen their monitoring and corrective action processes, which means complaints filed now will land in an environment where regulators are already under pressure to act.
• Request your MCO’s parity analysis. Under MHPAEA, MCOs are required to perform and maintain comparative analyses of their nonquantitative treatment limitations, including prior authorization. If your MCO cannot produce this analysis, that itself is a compliance failure identified in the OIG audits.
• Track denials at the code level. The most common psychiatry codes affected by prior authorization parity issues are the psychotherapy codes (90832, 90834, 90837), psychiatric evaluation codes (90791, 90792), and psychotherapy add-on codes. Build a denial tracking workflow that flags MCO-specific patterns on these codes.

Common Mistakes When Appealing Medicaid Denials

The most common mistake we see across the billing companies we vet is treating every Medicaid MCO denial as a documentation issue. When a denial is actually driven by a parity-noncompliant prior authorization policy, improving your documentation will not fix it. The denial will recur because the MCO’s authorization requirement itself is the problem, not the provider’s response to it.

A second mistake is appealing denials one at a time without identifying the systemic pattern. If your practice is seeing a consistent denial rate on psychotherapy prior authorizations from one MCO, that is not a series of individual claim problems. It is an MCO-level policy issue that should be escalated through the parity complaint process, not resolved through individual appeals.

A third mistake is assuming your state Medicaid agency is already monitoring parity compliance. The OIG audits found that Kansas did not request parity analyses from its MCOs at all, and Arizona’s oversight was unclear. If you assume someone else is watching, the denial pattern will continue unchecked.

For a broader look at how denial management fits into the overall revenue cycle for psychiatry practices, our guide on how to improve revenue cycle and billing management in behavioral health covers the operational framework.

In-House vs. Outsourced Parity Tracking

Tracking Medicaid MCO parity compliance is not something most in-house billing teams are set up to do. It requires comparing denial rates across benefit classifications, reviewing MCO provider manuals for differential treatment limitation policies, and filing formal complaints when disparities are identified. For a solo psychiatrist or small group practice, this work competes directly with claim submission, follow-up, and patient care.

In our experience matching providers with billing partners, the practices that catch parity-driven denials fastest are the ones working with a billing company that tracks denial rates by payer and by CPT code, not just by total volume. When a billing partner can show that your Medicaid MCO denies 90837 prior authorizations at twice the rate of comparable medical services, that data point is the beginning of a parity complaint, not just a revenue cycle metric.

The question for most psychiatry practice managers is not whether to track parity compliance but whether to build that capability in-house or bring in a billing partner that already has it. For practices with a significant Medicaid payer mix, outsourcing this function is often the faster and more cost-effective path because the billing company is already running the denial analytics across multiple practices and can identify MCO-specific patterns that a single practice would miss.

Frequently Asked Questions

Next Steps

Review your Medicaid MCO denial rates against your commercial and Medicare denial rates for the same psychiatry CPT codes. If your Medicaid MCO denials are consistently higher, document the pattern and file a parity inquiry with your state Medicaid agency.

If you are not tracking denial rates by payer and by code, start now. The data is the foundation for both parity complaints and for evaluating whether your billing workflow is capturing the revenue your practice earns.

A billing partner with behavioral health experience can run this analysis across your entire payer mix and identify where parity-driven denials are costing you the most.