Your Insurance Denied Therapy: How to Appeal Step by Step

You open your mail and find a letter from your insurance company. The Explanation of Benefits says “denied” next to the therapy session you attended three weeks ago. The reason code is a string of numbers that means nothing to you. Somewhere near the bottom, in small print, the letter mentions your right to appeal.

Most people stop here. They pay the bill out of pocket, absorb the cost, and assume the insurance company made the right call. They did not.

I bill insurance for therapy sessions every week. I have seen claims denied for reasons that range from clerical typos to deliberate misapplication of medical necessity criteria. The denial rate for behavioral health claims runs significantly higher than for medical and surgical claims, a disparity that federal law was supposed to eliminate over a decade ago. What I have also seen: patients who appeal their denials win more often than they expect.

This is a complete guide to appealing a therapy denial, written by a therapist who deals with insurance companies as part of daily clinical practice.

Why Insurance Companies Deny Therapy Claims

Before you write an appeal, you need to understand what went wrong. Denial reasons fall into a few categories, and each one requires a different response.

Common Denial Reasons

The denial letter itself contains critical information. It will list the specific reason for denial, the plan provision the insurer relied on, and your appeal rights including deadlines. Read the entire letter before doing anything else.

Step 1: Read the Denial Letter and Gather Information

Pull together these documents before you start writing anything:

• The denial letter or Explanation of Benefits (EOB) with the exact reason code and denial language
• Your insurance plan’s Summary of Benefits and Coverage (SBC) showing mental health benefits
• Your therapist’s clinical notes for the denied session(s)
• Your therapist’s treatment plan documenting your diagnosis, symptoms, and planned course of treatment
• Any prior authorization documentation if applicable
• Your plan’s appeals procedure, usually found in the member handbook or on the insurer’s website

Call member services and ask: “What are the specific clinical criteria you used to determine this service was not medically necessary?” Federal law requires the insurer to disclose the criteria they applied. Write down the representative’s name, the date, the call reference number, and exactly what they tell you.

Step 2: Determine Your Appeal Type

Insurance appeals follow a structured process. You cannot skip steps, but you should know the full path before you start.

Internal Appeal (First Level)

Every health plan must offer at least one level of internal appeal. Some offer two. During an internal appeal, the insurance company assigns a different reviewer to examine your case. This reviewer cannot be the same person or a subordinate of the person who made the original denial.

Deadline: Typically 180 days from the denial date. Check your specific plan.

What to submit: A written appeal letter, your therapist’s letter of medical necessity, supporting clinical documentation, and any relevant treatment guidelines.

Response time: The insurer must respond within 30 days for post-service claims (services already provided) and 72 hours for urgent pre-service claims.

External Appeal (Independent Review)

If the internal appeal is denied, or if the denial involves a question of medical necessity, you have the right to an external appeal. An Independent Review Organization (IRO) that has no financial relationship with your insurance company reviews your case. The IRO’s decision is binding on the insurer.

When to request: After exhausting internal appeals, or simultaneously if the denial involves medical necessity or an emergency.

Cost: Free. Federal and state law prohibit insurers from charging you for external review.

Response time: Typically 45 days for standard reviews, 72 hours for expedited reviews involving urgent care.

Expedited Appeal

If you are currently in treatment and the denial would interrupt your care, or if waiting for a standard appeal would seriously jeopardize your health, request an expedited appeal. You can request expedited internal and external reviews simultaneously.

Step 3: Write the Appeal Letter

The appeal letter is the most important document you will submit. It needs to be organized, specific, and grounded in your plan’s own language.

Appeal Letter Structure

Section 1: Identifying Information (top of letter)

Include your full name, date of birth, member ID number, group number, claim number, date of service denied, and the denial reference number from the EOB.

Section 2: Statement of Appeal

State clearly that you are filing a formal appeal of the denial. Reference the specific denial reason and date.

Example: “I am writing to formally appeal the denial of my claim for psychotherapy services (CPT 90837) on March 15, 2026, claim number 12345678, denied for reason code ‘not medically necessary’ as stated in the Explanation of Benefits dated March 28, 2026.”

Section 3: Clinical Argument

This is where you explain why the denied service is medically necessary. Reference your diagnosis, symptom severity, functional impairment, and treatment goals. Use your therapist’s clinical documentation to support each point.

Describe in concrete terms how your condition affects your daily functioning. “Generalized anxiety disorder” is a diagnosis. “Unable to attend work three days in the past month due to panic attacks, resulting in a written warning from employer” is evidence of medical necessity.

Section 4: Plan Language

Quote your plan’s own benefit description for mental health services. If the plan covers outpatient mental health treatment and your therapy qualifies as outpatient mental health treatment, state this explicitly.

Section 5: Parity Argument (if applicable)

If the denial reflects a limitation that does not apply to medical and surgical benefits, cite the Mental Health Parity and Addiction Equity Act. More on this below.

Section 6: Requested Action

State exactly what you want: reversal of the denial and payment of the claim.

Section 7: Attachments List

List every document you are including with the appeal.

What Your Therapist’s Letter Should Include

Ask your therapist to write a Letter of Medical Necessity that covers:

• Your DSM-5 diagnosis with ICD-10 code
• Date of onset and current symptom presentation
• Validated assessment scores (PHQ-9, GAD-7, PCL-5, or other relevant measures)
• Specific functional impairments in work, relationships, self-care, and daily activities
• Treatment modality being used and the evidence base supporting it
• Treatment plan with measurable goals and expected timeline
• Why less intensive alternatives are clinically inappropriate
• Consequences of discontinuing treatment

This letter carries more weight than anything else in the appeal. A detailed, well-structured letter of medical necessity from a licensed clinician converts denials into approvals at a rate that should embarrass the initial review process.

Step 4: Submit the Appeal

Send your appeal by certified mail with return receipt requested, or through the insurer’s secure online portal if one exists. Keep copies of everything.

If submitting by mail, send to the address listed in the denial letter under “How to Appeal.” This address is often different from the general claims address.

Create a tracking spreadsheet:

Follow up by phone if you have not received a written response within the required timeframe. Document every call.

Step 5: Escalate if the Internal Appeal Fails

If the internal appeal is denied, you have several paths forward.

File an External Appeal

Request an external review through the process described in your second denial letter. The IRO will conduct an independent review of your complete medical record, the appeal documentation, and the insurer’s clinical criteria. The IRO’s determination is final and binding on the insurer.

File a Complaint with Your State Insurance Commissioner

Every state has an insurance department or commissioner that regulates health insurance plans. Filing a complaint triggers a regulatory investigation. This is particularly effective when:

• The insurer failed to respond within required timeframes
• The denial violates state insurance regulations
• The denial appears to violate mental health parity requirements
• The insurer refused to disclose the clinical criteria used in the denial

Find your state’s insurance department at the National Association of Insurance Commissioners website (naic.org). Most states accept complaints online.

File a Complaint with the Department of Labor or HHS

If your insurance is through an employer-sponsored plan (ERISA plan), the Department of Labor oversees your plan. If your plan is a marketplace or individual plan, the Department of Health and Human Services has jurisdiction. File a complaint when you believe the insurer is systematically violating federal law.

The Mental Health Parity Act: Your Strongest Legal Tool

The Mental Health Parity and Addiction Equity Act (MHPAEA) of 2008, strengthened by the Affordable Care Act, requires group health plans that cover mental health to do so at parity with medical and surgical benefits. In practice, this means:

Quantitative limits must be equal. If your plan allows unlimited physical therapy visits, it cannot cap therapy sessions at 20 per year. If your medical deductible is $500, your mental health deductible cannot be $1,000.

Non-quantitative treatment limitations must be comparable. Prior authorization requirements, medical necessity criteria, and provider network standards for mental health must be no more restrictive than those applied to medical and surgical benefits. If the plan does not require prior authorization for a cardiology visit, requiring it for a therapy session may violate parity.

How to identify a parity violation:

If you identify a potential parity violation, include it in your appeal letter with specific comparisons to your plan’s medical and surgical benefits. Request the plan’s comparative analysis of mental health and medical/surgical benefits, which the plan is required to provide under federal law.

Common Mistakes That Sink Appeals

Missing the deadline. The appeal deadline is non-negotiable. Mark it on your calendar the day you receive the denial letter.

Writing emotional appeals without clinical evidence. The reviewer assessing your appeal is looking for clinical documentation, diagnostic criteria, and treatment necessity. “I really need therapy” is not as effective as “Patient meets DSM-5 criteria for Major Depressive Disorder, recurrent, severe, with PHQ-9 score of 22, and has been unable to maintain employment for three consecutive months.”

Not requesting the insurer’s clinical criteria. You have the right to know exactly what standard the insurer applied. If you do not know the criteria, you cannot argue against them.

Appealing the wrong denial. If the denial is for a coding error or missing information, a clinical appeal will not help. Fix the administrative problem and resubmit the claim instead of filing a formal appeal.

Giving up after the first internal appeal. The external appeal exists because internal appeals are reviewed by the insurer’s own staff. The IRO has no financial incentive to deny your claim.

When to Involve an Attorney or Patient Advocate

Consider professional help when:

• The denied claim exceeds $5,000
• The denial involves residential or inpatient treatment
• You have identified a clear parity violation and the insurer refuses to correct it
• The insurer has failed to comply with appeal timelines or disclosure requirements
• You are part of an ERISA plan and need to exhaust administrative remedies before litigation

Patient advocates and insurance billing specialists can also help draft appeals for a flat fee, typically $150 to $500 per appeal. Some therapists employ billing staff who handle appeals as part of their practice operations.

The Numbers Behind Denials

Insurance companies deny behavioral health claims at rates that exceed denials for other medical specialties. A 2023 KFF analysis of marketplace plans found denial rates ranging from 2% to over 40% depending on the insurer, with mental health and substance use claims disproportionately affected. Internal appeals succeed between 40% and 60% of the time for behavioral health claims, depending on the insurer and the quality of documentation submitted.

Those numbers mean roughly half of all therapy denials that are appealed get reversed. The patients who never appeal, who absorb the cost and assume the insurer was right, subsidize a system that profits from the friction of the process itself.

What to Do Right Now

If you are holding a denial letter:

1. Check the appeal deadline printed on the letter.
2. Call your therapist and ask them to prepare a Letter of Medical Necessity.
3. Call member services and request the clinical criteria used to deny your claim.
4. Compare your mental health benefits to your medical and surgical benefits for parity violations.
5. Write your appeal letter using the structure above and submit it before the deadline.

If you are starting therapy and want to prevent denials:

1. Verify your benefits before the first session, including prior authorization requirements.
2. Confirm your therapist is submitting claims with the correct CPT and diagnosis codes.
3. Keep every EOB you receive and review each one for accuracy.

The appeal process exists because insurers get it wrong. The system counts on patients who do not push back. Pushing back, with documentation and deadlines and the specific language of your plan’s own benefit structure, changes the math.