Behavioral Health Prior Authorization Rules

Key Takeaways

Prior authorization requirements for behavioral health vary by payer and plan, and they are most common for higher levels of care, psychological testing, and outpatient therapy beyond a session threshold.
Approvals are limited by code, number of units, and date range, so tracking each element keeps sessions inside what the payer approved.
Concurrent review requires updated treatment plans and progress documentation before a payer extends an approval.
Since January 1, 2026, Medicare Advantage plans, Medicaid and CHIP programs, and their managed care plans must decide standard requests within seven calendar days and expedited requests within 72 hours.
Federal parity law requires group health plans and other covered plans to apply prior authorization to mental health benefits no more stringently than to medical benefits.

A behavioral health claim can be coded correctly, documented well, and sent to the right payer and still deny because the session was never authorized or fell outside the dates and units the payer approved. Authorization rules differ by payer, plan, and service, and many apply only after a patient reaches a session threshold, which makes them easy to miss in an ongoing course of therapy.

Which Behavioral Health Services Typically Require Prior Authorization?

Prior authorization is most common for intensive levels of care, but many plans also require it for routine therapy. In 2022, according to KFF’s analysis of Medicare Advantage plans, the share of enrollees in plans requiring prior authorization, excluding special needs and employer plans, was:

93% for inpatient psychiatric hospital stays
91% for partial hospitalization
85% for opioid treatment program services
84% for therapy sessions with a psychiatrist, and 84% for therapy sessions with other mental health providers
83% for outpatient substance use disorder services

Commercial and Medicaid plans maintain their own lists, which can change at the start of a plan year. Psychological and neuropsychological testing commonly requires a separate request that specifies the tests and estimated hours, as covered in PGM’s guide to psychological testing codes. When a plan carves out behavioral health benefits, the authorization usually comes from a managed behavioral health organization, a distinction explained in PGM’s post on behavioral health carve-outs.

How Do Session Limits and Authorization Thresholds Work?

Many plans let therapy begin without authorization and require approval once a patient reaches a session threshold. Colorado’s Medicaid program is one example: starting January 1, 2026, its regional organizations may require prior authorization for outpatient psychotherapy beyond 24 sessions per member in a state fiscal year, according to the Colorado Department of Health Care Policy and Financing. The threshold counts any combination of the listed psychotherapy codes, including family and group psychotherapy, and excludes crisis psychotherapy codes, which are covered in our post on crisis, family, and interactive complexity billing.

Colorado’s threshold counts sessions per member across all provider types, so a patient who saw another therapist earlier in the year may reach it sooner than the practice’s own records suggest. Checking the payer’s count at intake, and again as the threshold approaches, keeps sessions from running past it.

What Is Concurrent Review in Behavioral Health?

Concurrent review is the payer’s periodic reassessment of ongoing treatment to decide whether to extend an authorization. The payer approves a block of sessions or days, then asks the practice for updated clinical information before approving more. Federal parity regulations at 29 CFR 2590.712 list the development and approval of a treatment plan used in a concurrent review process among the processes a plan uses to apply a limit such as prior authorization.

A continued-stay request generally needs:

The current diagnosis and treatment plan, updated to reflect the patient’s progress
Measurable goals and the patient’s progress toward them, often supported by rating scale scores
The reason continued treatment at the current level of care is needed
The number of additional sessions requested and the expected time frame

Which Authorization Details Should a Practice Track?

Every approval has limits on codes, units, and dates, and a service outside any one of them can deny. Tracking these fields for each active authorization keeps services inside the approval:

Field to track	Why it matters
Authorization number and issuing entity	Many payers require the number on the claim, and the issuer may be a managed behavioral health organization instead of the medical plan
Approved codes	An approval for individual psychotherapy does not cover testing, family psychotherapy, or a different level of care
Units or sessions approved and used	Services past the approved count deny even when the authorization is still within its dates
Start and end dates	Services outside the date range deny even when units remain
Rendering provider and location	Some approvals are tied to a specific clinician or site
Reauthorization due date	Sets the date to submit a continued-stay request before the approval runs out

What Happens When a Service Is Billed Without a Valid Authorization?

A claim for a service that required authorization and did not have one typically denies with Claim Adjustment Reason Code 197, which the X12 code list defines as precertification, authorization, notification, or pre-treatment absent. A service that exceeded the approved units or dates typically denies with CARC 198, defined as precertification, notification, authorization, or pre-treatment exceeded.

The options after an authorization denial depend on the payer:

Retroactive authorization. Some payers accept a request after the service if it arrives within their deadline, and others do not accept retroactive requests at all. The payer’s provider manual states which rule applies.
An appeal is appropriate when the practice obtained authorization and the payer failed to apply it, or when the payer’s records show the wrong dates or units. Include the approval letter or reference number.
Corrected claim. When the authorization existed but the claim omitted the number or listed the wrong one, a corrected claim with the right number resolves the denial.

What Do Federal Prior Authorization Rules Require of Payers?

Two CMS rules govern prior authorization for behavioral health services covered by Medicare Advantage, Medicaid, CHIP, and federal exchange plans:

Decision timeframes and denial reasons. Under the CMS Interoperability and Prior Authorization Final Rule (CMS-0057-F), Medicare Advantage organizations, Medicaid and CHIP fee-for-service programs, and Medicaid and CHIP managed care plans must decide expedited requests within 72 hours and standard requests within seven calendar days, generally beginning January 1, 2026. Those payers, along with Qualified Health Plan issuers on the federally facilitated exchanges, must also give a specific reason for each denial and publicly report prior authorization metrics, with the first set due March 31, 2026. The rule does not apply to prior authorization for drugs.
Medicare Advantage approval duration and transitions. Under the 2024 Medicare Advantage final rule (CMS-4201-F), effective January 1, 2024, a coordinated care plan’s approval for a course of treatment must remain valid as long as medically reasonable and necessary. A patient already in treatment who switches to a new Medicare Advantage coordinated care plan gets a transition period of at least 90 days during which the new plan cannot require prior authorization for that ongoing treatment.

Employer-sponsored commercial plans fall outside CMS-0057-F, so their timeframes follow the plan’s own terms and any applicable state law.

How Does Mental Health Parity Law Apply to Prior Authorization?

The Mental Health Parity and Addiction Equity Act treats prior authorization as a nonquantitative treatment limitation. Under the federal parity regulations, a plan that covers both medical and mental health benefits may not apply prior authorization to mental health or substance use disorder benefits unless the processes and standards behind it are comparable to, and applied no more stringently than, those used for medical and surgical benefits in the same classification. Numeric visit limits fall under a separate parity test, and a plan may not impose a visit limit that applies only to mental health or substance use disorder benefits and not to medical benefits in the same classification.

These requirements apply to group health plans, individual market coverage, and Medicaid managed care, but not to Medicare. The Department of Labor is not enforcing the provisions of the 2024 parity rule that are new relative to the 2013 rule, a policy it reaffirmed in September 2026. The statute and the 2013 rule remain in effect, as Mayer Brown’s summary explains. The Departments have committed to issuing a new proposed rule by December 31, 2026.

How PGM Supports Behavioral Health Prior Authorization

PGM has provided independent medical billing and revenue cycle management since 1981, with dedicated support for mental and behavioral health practices. Services include eligibility and benefits verification, prior authorization support, coding review, claims submission, denial management and appeals, and payment posting and reporting across commercial, Medicare, and Medicaid payers.

If authorization denials are holding up payment, talk to PGM’s behavioral health billing team. For what to expect from a specialized partner, see how to choose a behavioral health billing company.

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Frequently Asked Questions About Behavioral Health Prior Authorization

Does Original Medicare require prior authorization for psychotherapy?

No. Original Medicare does not require prior authorization for outpatient psychotherapy, although the services must still be medically necessary and documented. Medicare Advantage plans have their own requirements, and 98% of Medicare Advantage enrollees in 2022 were in plans that required prior authorization for at least one mental health or substance use disorder service, according to KFF.

Does an approved authorization guarantee payment?

No. An authorization confirms that the payer approved the service as medically necessary for the stated codes, units, and dates. The claim can still deny for eligibility, coding, documentation, or timely filing problems, so the authorization is one of several conditions for payment.

How far ahead should a practice request reauthorization?

A reauthorization request should go in early enough for the payer to decide before the approved units or end date run out. For Medicare Advantage, Medicaid, and CHIP plans, the federal standard decision time of seven calendar days sets the minimum lead time. Commercial plans follow their own timeframes, which the payer’s provider manual lists, and a request with incomplete clinical information can add time if the payer asks for more.

Does an authorization carry over when a patient switches clinicians within the practice?

Not always. Each authorization lists the services it covers, and many also list the rendering provider. When a patient moves to a different clinician within the practice, or adds a service such as family psychotherapy, check whether the existing approval applies or whether a new or amended request is needed before the next session.