How to appeal a medical-necessity denial in behavioral health

What does a medical-necessity denial mean in behavioral health?

It means a reviewer compared the clinical documentation with a set of criteria and concluded that the service, the setting or the amount of care was not justified for the dates in question. In behavioral health the dispute is usually about intensity, duration or frequency, not about whether the patient has a covered condition.

A medical-necessity decision can come at three points: before care starts (a prior-authorization or pre-service denial), during care (a concurrent-review or continued-stay denial), or after the claim is billed (a retrospective or post-payment review). The appeal path and the clock differ for each, so record which one you are dealing with before anything else.

Behavioral-health denials tend to follow a few patterns. A reviewer may say residential care is not needed because the patient could be treated in a partial hospitalization program (PHP); that a PHP stay should step down to intensive outpatient (IOP); that more sessions or ABA hours are not supported by measurable progress; or that withdrawal management could happen in a less intensive setting. If the notice says a lower level is appropriate, read the level-of-care denial guide; if days were cut mid-treatment, read the continued-stay guide.

A medical-necessity denial is different from an authorization denial (no authorization on file, or units over the authorized amount) and from a coding denial. Those usually carry other reason codes, such as CARC 197 or CARC 198, and are fixed differently.

What should you check before anyone drafts the appeal?

Confirm the review type, the exact dates and units denied, the reason in the plan's own words, the criteria it cites and the deadline. Then compare each stated gap with what was actually submitted. Many denials turn on a missing document rather than a clinical disagreement, and that changes the response.

1. 01Write down the member, the program, the level of care, the dates and units denied, and whether the denial is pre-service, concurrent or post-service.
2. 02Copy the stated reason word for word, and list each fact or criterion the reviewer says is missing.
3. 03Find the criteria set or guideline the notice names. If it names none, the notice may be incomplete; ask for the rule or protocol relied on.
4. 04Compare the reviewer's gaps with the records that were sent at the time. Note anything that was in the chart but never submitted.
5. 05Record the appeal deadline, the submission address or portal, and whether an expedited appeal or a peer-to-peer conversation is offered.
6. 06Assign the treating clinician to review the clinical facts, and decide who signs: the member, or the provider as authorized representative.

Which criteria did the reviewer use, and how do you get them?

Ask the plan in writing. Employer group health plans must make their mental health and substance use disorder medical-necessity criteria available on request to participants and contracting providers, and ERISA appeal rules give the claimant free access to the documents relevant to the claim. Medicaid managed care plans must provide the case file and criteria free of charge.

The criteria request does two jobs. It tells you which standard the reviewer applied, so the appeal can answer that standard point by point, and it creates a record if the plan used criteria stricter than generally accepted standards or than its own medical and surgical criteria. The criteria request letter tool drafts that request.

Under the ERISA claims rule, a denial notice for a group health plan must give the specific reason, the plan provision, and the internal rule, guideline or protocol relied on (or say that it is available free on request). For a medical-necessity denial it must also explain the scientific or clinical judgment behind the decision, or say that the explanation is available free on request.

How long do you have to appeal, by plan type?

It depends on who regulates the plan. Employer and Marketplace plans must allow at least 180 days to file an internal appeal. Medicaid managed care allows 60 days from the notice. Medicare Advantage allows 65 days. The notice itself controls if it gives more time, so always check it first.

The appeal deadline calculator applies these clocks to a notice date. Payer-specific steps, such as provider reconsiderations that come before the formal appeal, are in the payer guides.

What evidence answers a behavioral-health medical-necessity denial?

Evidence dated to the days in dispute that speaks to the reviewer's stated reasons: current symptoms and risk, functional impairment, response to less intensive care, co-occurring medical or substance use problems, and a treatment plan with measurable goals. General statements that the patient is struggling rarely move a reviewer.

Organize the evidence by the criteria the reviewer named. A short crosswalk that lists each stated gap, the record page that answers it, and the date is easier for a second reviewer to follow than a stack of notes. A letter from the treating clinician should explain the clinical reasoning in their own words; templates such as the IOP medical-necessity appeal letter show the structure but the clinical content must come from the record.

• Assessments and progress notes from the denied dates, not only from admission.
• Risk documentation: safety assessments, incidents, and why risk is not manageable at a lower level.
• Functioning at home, school or work, described with specific, observable examples.
• Treatment history: prior lower-level care, how long it lasted and why it did not hold.
• Scores from standardized measures the program already uses, with dates, to show severity or change.
• For ABA: assessment results, goal mastery data and the reason the requested hours are needed.

Should you ask for a peer-to-peer, an expedited appeal or a standard appeal?

If the patient is still in treatment and waiting could seriously jeopardize their health, ask for an expedited appeal and, if offered, a peer-to-peer conversation at the same time. For a closed episode or a retrospective denial, a standard written appeal with a complete record is usually the right path.

A peer-to-peer is an informal conversation between the treating clinician and the plan's reviewer. It can reverse a decision quickly, but windows are short and vary by payer, and some plans offer it only before the decision is final. The peer-to-peer guide covers preparation. An expedited appeal is a formal appeal with a 72-hour clock; under ERISA a request involving urgent care must be treated as urgent when a physician with knowledge of the patient's condition says it is.

What happens if the plan upholds the denial?

Most plans then offer an independent review. Non-grandfathered employer and Marketplace plans must offer external review by an independent reviewer; Medicaid enrollees can request a State fair hearing; Medicare Advantage reconsiderations that are upheld go to an independent review entity automatically. Independent reviewers overturn a meaningful share of behavioral-health denials.

In New York, independent reviewers overturned roughly six in ten mental health and substance use denials that reached external appeal from 2019 to 2025; the figures and their source are on our behavioral health denial statistics page. The external review request tool helps draft the request.

If the plan's criteria for a mental health or substance use service look stricter than the criteria it applies to comparable medical care, a parity question may also be worth raising. The parity warning-sign checker walks through the signs the Department of Labor has flagged.