Mental Health Parity: How to Appeal When Insurance Denies Therapy

Understanding Mental Health Parity: The Law on Your Side

The MHPAEA, passed in 2008 and significantly strengthened in recent years, requires that health plans offering mental health or substance use disorder benefits cannot impose restrictions more stringent than those applied to comparable medical or surgical benefits.

This applies to two types of limitations:

• Quantitative Treatment Limitations (QTLs): Hard caps, like visit limits. If your plan covers unlimited physical therapy visits, it generally cannot cap therapy sessions at 20.
• Nonquantitative Treatment Limitations (NQTLs): Non-numerical restrictions like prior authorization requirements, step therapy protocols, or medical necessity criteria. These cannot be more burdensome for mental health care than for comparable medical care.

Many insurers violate parity in subtle, hard-to-detect ways — applying stricter "medical necessity" criteria to mental health claims, requiring more prior authorizations for psychiatric medications, or using different network adequacy standards. Knowing this gives you a powerful argument.

Common Mental Health Denial Types and What to Do

"Not Medically Necessary"

This is the most common mental health denial. Your first step is to get your therapist or psychiatrist to write a detailed Letter of Medical Necessity documenting your diagnosis, functional impairment, treatment plan, and why continued care is clinically essential.

Arbitrary Visit Limit Reached

If your insurer cuts off coverage after a set number of sessions, this may be a parity violation. Document what comparable physical health benefits look like under your plan (e.g., physical therapy or cardiac rehab visit limits) and compare them.

Out-of-Network Mental Health Provider

Mental health provider networks are notoriously narrow. If you cannot find an in-network provider accepting new patients, you may have a right to out-of-network coverage at in-network rates through your plan's "network adequacy" requirements.

Inpatient or Residential Treatment Denied

Denials for inpatient psychiatric or substance use treatment are common and dangerous. Request an expedited appeal immediately. Your doctor's documentation of clinical necessity and risk of harm is critical.

Your Parity-Specific Appeal Strategy

Beyond the standard appeal process, a mental health appeal has a unique parity argument. Here is how to use it:

1. Request your insurer's NQTL analysis. Send a written request for the "comparative analysis" of nonquantitative treatment limitations for mental health vs. medical/surgical benefits. Under the Consolidated Appropriations Act of 2021, insurers must provide this analysis upon request. If they refuse or provide an inadequate analysis, that itself is a legal violation.
2. Identify the comparable medical benefit. For each restriction applied to your mental health claim, identify a comparable medical benefit where the same restriction is not applied. For example: "You require prior authorization for my therapy sessions but not for physical therapy visits."
3. Cite the law explicitly in your appeal letter. Reference the MHPAEA, 29 U.S.C. § 1185a (for employer plans) or its ACA counterpart. Insurers take parity claims seriously because the penalties for violations are significant.

Use our free appeal letter builder to create a professional letter and then add your parity argument.

Filing a Parity Complaint

If your appeals fail, filing a formal parity complaint is a powerful escalation tool. The appropriate agency depends on your plan type:

• Employer-sponsored (ERISA) plans: U.S. Department of Labor Employee Benefits Security Administration (EBSA)
• Individual/marketplace plans: Your state Department of Insurance and/or HHS
• Medicaid/CHIP: State Medicaid agency and CMS

You can also file a complaint through our state DOI complaint guide for additional pressure. Simultaneously escalating through multiple channels is effective.

External Review for Mental Health Denials

Like all clinical coverage denials, mental health denials are eligible for Independent External Review. This is often the most effective final step because independent reviewers apply clinical standards of care rather than your insurer's internal guidelines. For mental health cases, external reviewers also assess whether parity principles were applied.