Which CPT codes should I use for mental health services?

Common CPT codes include 90791 and 90792 for initial evaluations, 90832, 90834, and 90837 for psychotherapy sessions based on duration, 90833 as an add-on for therapy with medication management, 90839 for crisis psychotherapy, and 99213-99215 for E/M medication visits. Accurate selection depends on session length and service type.

What should I do if a mental health claim is denied?

Review the denial reason carefully. Common issues include timely filing, missing prior authorization, incorrect diagnosis codes, wrong CPT codes, or coordination of benefits errors. Correct the issue and resubmit the claim. If necessary, file an appeal with supporting clinical documentation and a clear explanation of medical necessity.

Should I handle mental health billing in-house or outsource it?

In-house billing works if you have trained staff managing coding, claims, and denials. Outsourcing is beneficial if denial rates are high, accounts receivable are aging, or administrative workload is excessive. Outsourced billing services can improve accuracy, reduce denials, and stabilize cash flow.

Mental Health Billing: 7 Questions Every Therapist and Psychiatrist Asks

Q: How is mental health billing different from regular medical billing?

Mental health billing is primarily time-based and includes services like psychotherapy, medication management, and diagnostic evaluations. Codes depend on session duration and provider type. Payer rules are stricter, often limiting sessions, requiring prior authorization, and enforcing detailed documentation of start and end times.

Q: Does insurance cover telehealth therapy sessions?

Yes, most insurers including Medicare and Medi-Cal cover telehealth therapy. Use the same CPT codes as in-person visits, add modifier 95 for telehealth, use Place of Service 10 for home or 02 for facility, and document patient consent and HIPAA-compliant platform use. Audio-only sessions may require modifier 93 depending on payer rules.

Q: How long do I have to file a claim after a session?

Filing deadlines vary by payer, typically ranging from 90 days to 12 months. For example, Aetna allows 90 days, while Medicare and Medi-Cal allow up to 12 months. Best practice is to submit claims within 30 days to avoid missing deadlines and to allow time for corrections if needed.

Q: Do I need prior authorization for therapy sessions?

Prior authorization depends on the payer and plan. Some require it for initial evaluations, crisis therapy, or extended treatment beyond a set number of sessions. Always verify requirements before the first appointment and monitor session limits to avoid denials.

If you’re a therapist, psychologist, or psychiatrist in Southern California, you already know that the clinical work is the easy part. It’s the billing the codes, the prior authorizations, the denials, the payer rules that takes up hours you don’t have.

We work with mental health providers across Orange County, Los Angeles, San Diego, and the Inland Empire every day, and the same questions come up over and over. So we put the answers in one place.

Here are the 7 most common billing questions mental health providers ask and what you actually need to know.

Q1: How is mental health billing different from regular medical billing?

This is the first thing most providers want to understand, and the gap is bigger than most people expect.

In standard medical billing, services are tied to specific, measurable procedures — an x-ray, a lab panel, a surgery. Mental health billing works differently. You’re billing for time-based therapy, medication management, psychological testing, and diagnostic evaluations. There’s no fixed physical procedure code for a 45-minute session — the code depends on exactly how long the session lasted and who provided it.

The payer rules are also stricter in behavioral health. Insurers often limit the number of sessions they’ll cover per year, restrict which CPT codes a therapist can bill versus a psychiatrist, and apply prior authorization requirements that don’t exist in general medical billing.

For a full breakdown of how we handle mental health coding for practices in Southern California, visit our Mental Health Billing services page.

What this means for your practice:

A coding error that misses a session length by 10 minutes can cost you the entire claim. Accurate documentation of start and end times is not optional it’s the foundation of getting paid.

Q2: Which CPT codes should I actually be using?

Mental health services use a small set of CPT codes, but choosing the wrong one is one of the most common reasons claims get denied or down coded. Here’s a working reference:

CPT Code	Service	Session Length	Common Use
90791	Psych Diagnostic Eval	N/A (intake)	First appointment — no medication review
90792	Psych Diagnostic Eval w/ Medical	N/A (intake)	Psychiatrists conducting intake with Rx review
90832	Individual Psychotherapy	16–37 min	Brief therapy or check-ins
90834	Individual Psychotherapy	38–52 min	Most common — standard therapy session
90837	Individual Psychotherapy	53+ min	Full 60-min sessions (document carefully)
90833	Psychotherapy Add-On	30 min	Added to E/M code — medication + therapy same visit
90839	Crisis Psychotherapy	30–74 min	Crisis intervention (must document medical necessity)
99213–99215	E/M Visit	Varies	Psychiatrists billing medication management only

The most important thing to know: 90834 is the most commonly billed code for ongoing therapy. 90837 (60-minute sessions) is fine to use, but payers like Aetna and Medicare scrutinize it closely. If your documentation doesn’t clearly support 53+ minutes of face-to-face time, use 90834.

For psychiatrists: You’ll typically use E/M codes (99213–99215) for medication management visits, and add 90833 on top when you also provide 30 minutes of psychotherapy in the same appointment.

Q3: Does insurance cover telehealth therapy sessions?

Yes and this has been one of the biggest changes in mental health billing over the last few years. Most commercial insurers, Medi-Cal, and Medicare now cover telehealth therapy for mental health services. But the rules around how to bill it still trip providers up.

What you need to do:

Use the same CPT code you would for an in-person session (90834, 90837, etc.)
Add modifier 95 to indicate the service was delivered via telehealth
Set the Place of Service code to 10 if the patient is at home, or 02 if they’re at a facility
Use audio-only sessions? Add modifier 93 coverage varies significantly by payer
Document that the session was conducted via a HIPAA-compliant video platform and that the patient consented

California-Specific Note:

California has strong telehealth parity laws. Most commercial plans are required to reimburse telehealth at the same rate as in-person visits. Always verify with each individual payer before assuming reimbursement rates are equal.

Q4: How long do I have to file a claim after a session?

This is more urgent than most providers realize and missing a filing deadline is one of the few billing errors that can’t be fixed. Once the window closes, that revenue is gone.

Filing deadlines vary by payer:

Aetna: 90 days from date of service
Blue Cross Blue Shield: typically 90–180 days (check your contract)
United/Optum Behavioral Health: varies by plan, often 90–180 days
Medicare: 12 months from date of service
Medi-Cal (California): 12 months from date of service

Best practice:

Submit claims within 30 days of service regardless of payer. The sooner a claim is submitted, the sooner you catch any errors and have time to correct and refile within the deadline window.

Q5: What do I do when a claim is denied?

Denials are not the end of the road they’re a request for more information or a correction. Most mental health billing denials fall into a handful of categories:

Timely filing: Claim submitted outside the payer’s window. Prevention is the only cure.
No prior authorization: The payer required it and didn’t receive it before the session. Call the insurer immediately and request a backdated authorization it doesn’t always work, but it sometimes does.
Incorrect or missing diagnosis code: Payers are increasingly rejecting claims with unspecified ICD-10 codes. Use the most specific diagnosis available (e.g., F32.1 for major depression, moderate not F32.9, unspecified).
Wrong CPT code or modifier: A mismatch between the service billed and the documentation. Review the note and refile with the correct code.
Coordination of Benefits (COB) issue: The patient has changed insurance. Verify coverage at every visit, not just intake.

You have the right to appeal any denial. Most payers have a formal appeals process. Submit your appeal with clinical notes, the original claim, and a written justification for medical necessity.

Managing denials is one of the most time-consuming parts of running a practice. Learn how our Denials Management & Appeals keep your AR clean and your cash flow consistent.

Q6: Do I need prior authorization for therapy sessions?

It depends entirely on the payer, the service, and the patient’s plan. The short answer: always check before the first session.

Some commercial plans require prior authorization for:

Initial psychiatric evaluations (90791, 90792)
Certain diagnostic testing codes
Intensive outpatient programs (IOP)
Extended or crisis psychotherapy (90839)

Ongoing individual therapy (90834, 90837) often doesn’t require prior auth for the first few sessions, but many plans build in a limit say, 20 sessions after which you need to submit a treatment plan for continued authorization.

For psychiatrists managing both medication and therapy in the same visit, some payers require prior auth specifically for the combined billing (E/M + 90833 add-on). Verify before you bill.

Q7: Should I handle billing in-house or outsource it?

This is the question that comes up at the end of every other conversation. And the honest answer depends on where your time goes.

In-house billing works when you have a dedicated staff member who understands behavioral health coding, stays current on payer rule changes, and actively manages your AR and denial follow-up. That’s a significant investment.

Outsourcing makes sense when:

Your denial rate is above 10% of submitted claims
Claims are sitting in AR past 60–90 days without follow-up
You’re spending more than a few hours per week on billing administration
You’re unsure whether you’re coding sessions correctly
You don’t have bandwidth to appeal denials

How Claim N Billing works:

We specialize in mental and behavioral health billing for practices across Orange County, Los Angeles, San Diego, and the Inland Empire. Our fee is 5–8% of collections no upfront costs, no long-term contracts. You pay us only when you get paid.

We handle claim submission, denial management, prior auth follow-up, and AR recovery so you can stay focused on your patients.

The Bottom Line

Mental health billing is more complex than most providers expect when they start their practice. The CPT codes are time-sensitive, the payer rules are inconsistent, and the filing deadlines don’t move. A single documentation gap or missed modifier can cost you weeks of delayed payments or a denied claim that’s hard to recover.

If you’re spending time on billing that should be going toward patient care, it’s worth having a conversation about what a billing partner could do for your practice.

Get a Free Billing Audit

We’ll review your current billing process and show you exactly where revenue is slipping through the cracks.

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