How to Appeal an Insurance Denial
Insurance denials for addiction treatment are common, and frequently overturned on appeal. A denial is not a final answer. It is the beginning of a process that families who know their rights can often win. This guide walks through every step of that process, from internal appeal through external review and regulatory complaint.
Medically Reviewed by:
Dr. Darrin Mangiacarne
Chief Medical Officer
At Banyan Treatment Centers, Chief Medical Officer Dr. Darrin Mangiacarne leads our nationwide clinical team with over a decade of addiction medicine experience, helping ensure evidence-based, compassionate care across every level of treatment.
Author / Written by: Banyan Editorial Staff
Medically reviewed by: Dr. Darrin Mangiacarne, CMO
Updated on: June 2026
Family Resources Hub › Substance Use Resources › How to Appeal an Insurance Denial
Why Insurance Denies Addiction Treatment and Why Appeals Work
Insurance denials for addiction treatment fall into a few common categories: not medically necessary, wrong level of care, provider not in-network, missing prior authorization, or plan exclusion. The most common is "not medically necessary", the insurer's reviewers have determined that the clinical documentation does not meet their internal criteria for the requested level of care.
The important thing to understand is that many of these denials are incorrect, either because the internal criteria being applied violate the Mental Health Parity Act, because the clinical documentation was incomplete, or because the reviewer made an error. Studies have consistently found that a significant percentage of addiction treatment denials are overturned on appeal when the family and treatment team engage the process actively.
Every insurance plan is legally required to provide a written explanation of any denial and information about how to appeal it. The appeals process has multiple stages, and at each stage, the odds of success improve with better documentation and more specific arguments.
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How to Appeal an Insurance Denial
There are four levels of appeal available. Most denials are resolved at the first or second level when the right documentation is provided. Go through each level in order, and document everything at every step.
Peer-to-Peer Review — Request This First
Before filing a formal appeal, request a peer-to-peer review, a direct phone conversation between your loved one's treatment provider (physician or clinical director) and the insurance company's medical reviewer. This is the single most effective step and overturns a significant percentage of initial denials without a formal appeal process.
How to request it: Call member services and ask: "I'd like to request a peer-to-peer review of this denial." The insurer is required to make this available. Treatment programs typically handle this call on your behalf.
What to have ready: The treating clinician should be prepared to discuss the specific ASAM criteria that support the requested level of care, co-occurring diagnoses, safety concerns, and why a lower level of care is clinically insufficient.
Internal Appeal — The Formal First Step
If the peer-to-peer review does not resolve the denial, file a formal internal appeal with the insurer. Under the ACA, insurers must respond to internal appeals within specific timeframes: 72 hours for urgent/expedited appeals, 30 days for pre-service claims, and 60 days for post-service claims.
Your internal appeal letter should include:
- A clear statement of what you are appealing and why you believe it should be covered
- A clinical letter from the treatment provider documenting the ASAM criteria supporting the level of care
- The insurer's own stated criteria and an argument for why the patient meets them
- A statement invoking the MHPAEA and requesting identification of the comparable medical benefit
- Any relevant clinical notes, assessments, or documentation of prior treatment history
Important: Send the appeal by certified mail with return receipt, and keep copies of everything.
External Appeal — Independent Review
If the internal appeal is unsuccessful, you have the right to an external appeal, an independent review by a qualified reviewer who is not employed by or affiliated with the insurance company. External reviewers overturn insurance denials at surprisingly high rates for addiction treatment.
For individual and small group plans: Request external review through your state insurance commissioner's office.
For employer-sponsored plans: Request external review through the insurer's process. Under the ACA, external appeal decisions are binding on the insurer.
Include all the same documentation from your internal appeal plus the insurer's denial letter and any additional clinical information.
Regulatory Complaints — Parallel Track
Filing a regulatory complaint can be pursued alongside the appeals process, it is not necessary to wait for appeals to be exhausted before filing. Regulatory complaints create scrutiny and a documented record that often motivates insurers to reconsider.
- State insurance commissioner: For individual, marketplace, and fully insured group plans. Contact your state's Department of Insurance.
- Department of Labor (EBSA): For employer-sponsored self-insured plans. File at askebsa.dol.gov.
- CMS: For Medicaid managed care denials. Contact your state Medicaid agency and CMS.gov.
- State attorney general: For suspected systemic MHPAEA violations by large insurers.
What to Gather Before You File
From the Treatment Provider
- Letter of medical necessity citing specific ASAM criteria
- Clinical assessments and diagnostic documentation (DSM-5 criteria)
- Documentation of co-occurring mental health conditions
- Prior treatment history and outcomes
- Safety and risk assessment
- Specific explanation of why a lower level of care is clinically insufficient
From Your Records
- The insurer's denial letter with the specific reason for denial
- Your insurance card and policy/plan documents
- Notes from your benefits verification call (date, time, rep name, reference number)
- Any prior correspondence with the insurer
- Summary Plan Description (for employer plans) request from HR
- Prior authorization documents (if any were submitted)
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Related Guides
The Mental Health Parity Act
The legal framework that makes many insurance denials for addiction treatment challengeable.
Read the guide →Does Insurance Cover Addiction Treatment?
What insurance is legally required to cover — the foundation of any appeal argument.
Read the guide →How to Verify Your Insurance Benefits
How to establish a documented benefits baseline before admission — which strengthens any future appeal.
Read the guide →What If I Can't Afford Treatment?
Alternative funding options if the appeal is ultimately unsuccessful.
Read the guide →Does My Loved One Need Residential?
Clinical documentation that supports residential authorization — the core of any medical necessity appeal.
Read the guide →How Long Does Rehab Take?
Why treatment duration matters — and how to argue for longer authorization when initial approval is limited.
Read the guide →Additional Resources
Tools, community, and organizations to support your family's journey.
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Read the Banyan blog →Insurance & Financing
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