Why Add-On Psychotherapy Codes Are the Most Consistently Underbilled Codes We Audit

Across roughly 50 behavioral health practices we work with at Revenant Care Group, one pattern shows up in nearly every audit: psychiatrists and psychiatric nurse practitioners are conducting medication management visits that include meaningful psychotherapy, billing only the E/M code, and leaving the add-on psychotherapy code off the claim entirely. We are talking about CPT codes 90833, 90836, and 90838, three add-on codes that attach to E/M services and reimburse separately for 16-37 minutes of psychotherapy delivered in the same session. The revenue is there. The documentation often supports it. The code never gets submitted.

This is not a gray area or a compliance risk. The AMA and CMS explicitly designed these codes to capture the clinical reality of psychiatric practice, where a prescriber and patient often do both medication review and psychotherapy in a single encounter. The problem is operational: charge capture workflows are not built to prompt the add-on, documentation templates do not consistently capture psychotherapy time, and billing staff frequently do not know how to pair these codes correctly. The result is a measurable revenue gap that compounds month over month. This post walks through exactly how these codes work in 2026, what correct billing looks like, and where the dollars are hiding.

How CPT 90833, 90836, and 90838 Actually Work

These three codes are add-on psychotherapy codes, meaning they cannot be billed alone. Each one attaches to a specific E/M base code and represents a specific psychotherapy time block delivered in the same encounter:

• CPT 90833: 16-37 minutes of psychotherapy added to an outpatient E/M (most commonly 99213 or 99214). This is the highest-volume pairing in outpatient psychiatric practice.
• CPT 90836: 16-37 minutes of psychotherapy added to an outpatient E/M when the patient is seen in an office or outpatient setting with a different E/M base code tier.
• CPT 90838: 38 or more minutes of psychotherapy added to an E/M, used when the psychotherapy component is substantial and well-documented.

Place of Service (POS) matters here. POS 11 (office) is the standard setting for these codes in outpatient psychiatric practice. POS 02 (telehealth) is also valid and widely covered following the telehealth flexibilities that most major payers have now permanently adopted or extended through 2026. The psychotherapy time must be documented separately from the E/M medical decision-making, and the documentation must support both components independently. That dual-documentation requirement is where most practices fall short, not because the service was not performed, but because the template was not built to capture it.

What the Revenue Gap Looks Like at Practice Scale

Let us put real numbers to this. The 2026 Medicare Physician Fee Schedule places the non-facility (office) allowable for CPT 90833 at approximately $68 to $74 depending on geographic locality. Commercial payers frequently reimburse at 110-130% of Medicare for psychiatric add-ons, particularly in states with mental health parity enforcement. That puts the average blended rate for 90833 at roughly $75 to $95 per unit across a typical payer mix.

Now scale that. A psychiatrist seeing 18 patients per day with a conservative 40% rate of encounters that legitimately include billable psychotherapy has roughly 7 add-on opportunities daily. At 220 clinical days per year and a blended rate of $82 per unit, that is approximately $126,280 in annual revenue per full-time prescriber if the add-on is billed correctly. We regularly audit practices with two to five prescribers who have billed zero units of 90833 in the prior 12 months. At a three-prescriber practice, that is a potential recovery corridor of $250,000 to $380,000 annually, depending on payer mix and clinical volume.

CPT 90838 (38+ minutes of psychotherapy) is less frequent but reimburses at approximately $115 to $135 per unit in 2026. Practices that do longer integrative sessions and never bill 90838 are leaving their highest-value encounters unbilled at the add-on level.

The Documentation Requirements You Cannot Shortcut

The single biggest audit risk and billing failure point for these codes is documentation. CMS and commercial payers require that the medical record clearly show two distinct clinical components: the E/M portion and the psychotherapy portion. Specifically, the note must reflect:

• The total face-to-face time of the encounter
• The time spent specifically on psychotherapy (minimum 16 minutes for 90833 and 90836)
• The content and nature of the psychotherapy provided (not just “supportive therapy discussed”)
• That the psychotherapy was distinct from the counseling and coordination of care elements counted in the E/M

This is where most EHR templates fail practices. A standard psychiatric SOAP note captures HPI, mental status exam, medication review, and plan. It does not prompt the provider to document psychotherapy time separately or describe the modality and content of the psychotherapy component. Fixing this is a template problem, not a compliance problem, and it is fixable in a single afternoon of EHR configuration work. We routinely help practices build this into their note templates during onboarding so the documentation supports the billing from day one.

Payer-Specific Denials and How to Fight Them

When practices do start billing 90833 or 90838 correctly, they often encounter a new problem: denials. The most common denial patterns we see on these add-on codes include:

• Bundling edits: Some payers incorrectly apply NCCI edits that bundle the add-on into the base E/M. This is wrong. These codes are specifically excluded from standard bundling rules when billed with the correct base E/M. Appeal with the AMA CPT guidance and the CMS NCCI manual citation.
• Medical necessity denials: Payers sometimes deny 90838 as not medically necessary without requesting records. Respond with the session note and a letter citing the treating provider’s clinical rationale.
• Unlisted provider type denials: Some payers have credentialing rules that limit psychotherapy add-ons to licensed therapists and incorrectly deny them when billed by a psychiatric NP or MD. This is a MHPAEA-relevant issue in many cases. Practices facing this pattern should review their parity obligations carefully. We cover the appeal framework for exactly this type of denial in our post on MHPAEA parity appeals and behavioral health revenue recovery.

Denial recovery rates on correctly documented 90833 and 90838 claims that were initially denied range from 62% to 81% based on our internal data across payers. The appeals are winnable. Most practices never file them because the add-on was never billed in the first place.

Building the Charge Capture Workflow That Prevents Revenue Leakage

The fix is procedural, not clinical. Prescribers are already doing the work. The billing system just needs to capture it. The workflow changes that close most of the gap in our experience include:

• Adding a psychotherapy time field to the encounter note that is required before the note can be closed
• Building a charge capture prompt in the EHR or practice management system that asks “Was psychotherapy provided?” at the point of charge entry
• Training schedulers to flag appointment types that are likely to include psychotherapy so billing staff review those encounters with add-on codes in mind
• Running a monthly CPT frequency report comparing 90833/90836/90838 units to total psychiatric E/M volume as a utilization benchmark

This is the same operational discipline we apply to other high-leakage code categories in behavioral health. If your practice also provides substance use disorder services and includes point-of-care drug screening, the revenue recovery principles are similar. Our breakdown of G0480-G0483 drug screen coding and SUD revenue recovery shows how systemic undercoding across service lines compounds into significant annual losses.

Take Action This Week

If your psychiatric prescribers are seeing patients in outpatient or telehealth settings and your 90833 billing volume is near zero, or if your 90838 utilization has never been reviewed against clinical volume, you almost certainly have a recoverable revenue gap. The billing logic is clean, the codes are valid, and the payer appetite for correctly documented claims is there. What is missing in most practices is the audit that surfaces the problem and the workflow that prevents it going forward. Revenant Care Group offers a free 30-day denial and undercoding audit specifically designed for behavioral health and psychiatric practices. If you want to see exactly where your add-on code revenue is leaking and what it would take to recover it, schedule your free audit session here and we will get into your claims data within the week.