Behavioral Health Billing Denials: Causes and Fixes

Most behavioral health billing denials come from a short list of causes: a psychotherapy code the minutes in the note don't support, an add-on code billed without its E/M visit, a claim sent to the health plan when a separate company manages the mental health benefit, a telehealth claim missing what the payer asks for, and notes that don't show time or medical necessity. Each one can be caught before the claim goes out, at the front desk or in the note.

Here is each cause, the reason code it usually comes back with on your remittance, and what to change.

Psychotherapy is billed by the minute

The standalone psychotherapy codes are chosen by the time spent in psychotherapy with the patient or a family member, not by the length of the appointment:

Less than 16 minutes isn't reported as psychotherapy. Medicare's contractors expect the exact time in the record (CGS fact sheet for LCD L34353), and any payer that reviews a note will look for it.

Where practices go wrong:

• Billing the slot, not the session. A 45-minute appointment where therapy ran 36 minutes is 90832, not 90834.
• Time that isn't in the note. No minutes, or the same "45 minutes" pasted into every note, leaves nothing to support the code if the payer asks for records, and a paid claim can be taken back after a review.
• 90837 by habit. The 60-minute code needs 53 minutes documented. A clinician who bills it for nearly every session should expect payers to ask for notes.

Therapy in a medication visit uses the add-on codes

When a psychiatrist, psychiatric nurse practitioner or other prescriber does an E/M visit and psychotherapy in the same visit, the therapy is billed with an add-on code beside the E/M code, never with 90832, 90834 or 90837:

Two rules cause most denials here. First, the add-on can't stand alone: without the E/M line on the same claim, it is denied. Second, the two services have to be separate in the note. Minutes spent on the E/M work (the medication review, the history, the decisions) don't count toward the psychotherapy time, and therapy minutes don't count toward an E/M level chosen by time.

Interactive complexity, 90785, is another add-on, billed with psychotherapy or an evaluation when something specific made communication harder, such as using play equipment with a child. The note has to say what it was.

The behavioral health page's tool, "Find the psychotherapy code", gives the code from the minutes and whether there was an E/M visit.

Evaluations: 90791 and 90792

A psychiatric diagnostic evaluation is 90791, or 90792 when a prescriber adds medical services such as a medication review or a physical exam. Psychologists, counselors and social workers bill 90791; 90792 is for clinicians who can provide medical services.

Two rules to know. Under Medicare's National Correct Coding Initiative, the same practitioner doesn't report either code with an E/M or psychotherapy code on the same date (NCCI Policy Manual, chapter XI). And Medicare contractors cover the evaluation once at the start of an illness, with exceptions set out in their coverage policy (CGS), so a repeat evaluation needs a documented reason. The full comparison is in CPT 90791 vs 90792.

The plan on the card may not process the claim

Many health plans hand their mental health benefits to a separate behavioral health company, often called a carve-out. The card names the health plan, but therapy claims go to the other company, with its own payer ID and its own network. A claim sent to the medical plan comes back with reason code 109: not covered by this payer, send it to the correct one (X12 claim adjustment reason codes).

Before the first session, check:

• Which company manages the behavioral health benefit. A separate behavioral health phone number on the card is the usual clue; confirm it with the plan.
• Whether this clinician, not just the practice, is in that company's network.
• The copay, coinsurance and deductible for outpatient mental health, in the office and by telehealth.
• Any limit on sessions, and whether the plan requires authorization for the service.
• The coverage dates, so a plan that ended doesn't surface weeks later as reason code 27, "expenses incurred after coverage terminated".

Check again at each new plan year and whenever a patient mentions a new job or plan.

Session limits and authorizations

Some plans limit the number of covered sessions, within what mental health parity law allows, or require authorization for certain services, most often intensive outpatient and partial hospitalization programs. An authorization covers a set number of sessions between two dates.

Keep your own log for each patient who has one: the authorization number, sessions approved, sessions used and the end date. Ask the plan about more sessions before the last approved one, not after. A session past the limit comes back as reason code 119 (benefit maximum reached), and one with no authorization as 197.

Telehealth claims

Video and phone sessions use the same psychotherapy codes, plus the details each payer asks for:

• Place of service. CMS's code set has POS 02 for telehealth when the patient isn't at home and POS 10 when they are (CMS place of service codes). Some payers want the office's place of service instead, with a telehealth modifier.
• Modifier. Payers that ask for one commonly use 95 for a live video visit, and 93 for an audio-only visit where they cover audio-only care.
• The note. It should say the session was by video or phone and where the patient was.

The rules differ between Medicare, each state's Medicaid program and each commercial plan, and they have changed often since 2020. Check the payer's current telehealth policy, not last year's.

Each clinician enrolled with each plan

A claim for a clinician who isn't credentialed with the plan, or with the company that runs its behavioral health network, is denied or paid as out of network. Medicare has enrolled marriage and family therapists and mental health counselors since January 1, 2024 (CMS), so a practice with those clinicians may have Medicare enrollments to set up as well. Start credentialing and enrollment well before a new clinician's first session.

Notes that show medical necessity

Payers pay for psychotherapy that is medically necessary, and the note is the evidence. One Medicare contractor's checklist (CGS) asks for the time, the type of therapy and how often, the diagnosis, symptoms, functional status, a focused mental status exam, the treatment plan with progress, and the clinician's name, credentials and signature.

A note that reads the same every week, with no change in symptoms or goals, is hard to defend when a payer reviews ongoing treatment. Medical-necessity denials come back as reason code 50.

Filing deadlines and working denials

Each payer sets a deadline for filing claims. Medicare's is 12 months from the date of service (42 CFR 424.44); commercial plans and behavioral health companies set their own in their contracts, often shorter. Late claims come back as reason code 29, and corrections and appeals have deadlines of their own.

A simple routine:

1. Look at denials every week, not when someone has time.
2. Sort them by reason code and payer. The same code from the same payer twice is a process problem, not bad luck.
3. Fix the cause where it starts: the note template, the front-desk check or the authorization log.
4. Keep each payer's appeal deadline beside every open denial.

Frequently Asked Questions

Why are mental health claims denied?

Most often for a time code the note doesn't support, an add-on billed without its E/M visit, a claim sent to the wrong company, a missing authorization or telehealth detail, a clinician who isn't enrolled, or a note that doesn't show medical necessity.

Which code do I bill for a 50-minute therapy session?

90834, which covers 38 to 52 minutes of psychotherapy. 90837 needs 53 minutes or more, documented in the note.

Can I bill 90837 with an E/M visit on the same day?

No. When psychotherapy is part of an E/M visit, it is billed with the add-on codes 90833, 90836 or 90838, chosen by the same time ranges.

How quickly should a denied claim be resubmitted?

As soon as the cause is fixed, and well inside the payer's deadline for corrected claims or appeals. Waiting risks missing that deadline and losing the claim.

Where Beeline fits

Beeline is a US company with a dedicated billing team, and behavioral health billing is one of the specialties it handles: benefits checked before the first session, psychotherapy coded from the documented time, claims sent to the company that processes them, and denial management that traces each denial to its cause. The denial management page's tool, "The denial decoder", explains the common reason codes in plain words. To have someone look at your own denials, book a free consultation.