Back to Afia

F31 — ICD-10 codes for bipolar disorder

Bipolar disorder is the diagnosis where the code changes between visits. Unlike most ICD-10 codes, the F31 family encodes the current episode — manic, depressed, mixed, hypomanic or in remission — so a patient whose state has changed needs a different code, not the one carried forward from last time. F31.9 is unspecified and F31.81 is Bipolar II, which is easy to miss because it sits away from the episode codes. Below: the family, and what the fourth and fifth characters are doing.

This page is billing and administrative reference. It describes what a code means and whether it can be submitted. It is not clinical advice and does not tell anyone what to diagnose.

The habit that causes the errors

Most diagnoses are stable: generalized anxiety disorder is F41.1 today and F41.1 next month. Bipolar is not. The code records the episode the patient is in at that encounter, so carrying last visit's code forward is wrong whenever the state has moved — and in bipolar disorder it moves.

Practically: a patient coded F31.31 (current episode depressed, mild) who presents hypomanic is F31.0 at that visit. The historical code is not corrected; the new encounter simply carries the accurate current one.

The F31 family

CodeCurrent episodeBillable?
F31.0HypomanicYes
F31.1Manic without psychotic features (incomplete)No
F31.10… unspecifiedYes
F31.11 / .12 / .13… mild / moderate / severeYes
F31.2Manic, severe, with psychotic featuresYes
F31.3Depressed, mild or moderate (incomplete)No
F31.30… mild or moderate severity, unspecifiedYes
F31.31 / .32… mild / moderateYes
F31.4Depressed, severe, without psychotic featuresYes
F31.5Depressed, severe, with psychotic featuresYes
F31.6Mixed (incomplete)No
F31.60 – F31.64Mixed, unspecified through severe with psychotic featuresYes
F31.70 – F31.78In remission, by most recent episodeYes
F31.81Bipolar II disorderYes
F31.89Other bipolar disorderYes
F31.9Bipolar disorder, unspecifiedYes

Bipolar II sits apart — F31.81

Worth calling out because it is easy to miss. Bipolar II is not coded by current episode in the way Bipolar I is; it has its own code, F31.81, regardless of the current state. A clinician scanning the episode list for something matching a depressed presentation can land on an F31.3 or F31.4 code when F31.81 is the accurate one.

Which codes need a fifth character

F31.1, F31.3 and F31.6 are incomplete and will be rejected on their own. F31.0, F31.2, F31.4, F31.5, F31.81, F31.89 and F31.9 are complete as written. That asymmetry is the second most common source of rejected bipolar claims after carrying the wrong episode forward.

CPT codes billed with F31

CPTServiceTime
90791Psychiatric diagnostic evaluation (no medical services)—
90832Individual psychotherapy16–37 minutes
90834Individual psychotherapy38–52 minutes
90837Individual psychotherapy53 minutes or more
90847Family psychotherapy, patient present50 minutes typical
90853Group psychotherapy—

A 50-minute session is 90834, not 90837 — 90837 begins at 53 minutes.

Bipolar care frequently involves medication management. Prescribers billing an evaluation and management visit alongside therapy use the add-on codes 90833, 90836 or 90838 rather than a standalone psychotherapy code.

DSM-5 crosswalk

DSM-5-TR prints the ICD-10-CM codes beside its bipolar diagnoses, and the structure matches: Bipolar I is coded by current episode across the F31 range, and Bipolar II is F31.81. Cyclothymic disorder is separate again at F34.0.

Check it live

Afia is free and answers these by voice or chat — find a code from a condition name, confirm whether a code is billable, validate a whole list at once, or check a session length against a CPT time band. No sign-up.

Frequently asked questions

What is the ICD-10 code for bipolar disorder?

There is no single code. F31 encodes the current episode, so the right code depends on whether the patient is currently manic, depressed, mixed, hypomanic or in remission. F31.9 is bipolar disorder, unspecified.

What is the ICD-10 code for bipolar II?

F31.81. It sits apart from the episode-based codes and applies regardless of the current state, which is why it is easy to miss.

Does the bipolar code change between visits?

Yes, and this is the main difference from most diagnoses. The code records the episode at that encounter, so a patient who presents hypomanic after being coded as depressed carries a different code for the new visit. Earlier encounters are not changed.

Is F31.1 billable?

No. F31.1, F31.3 and F31.6 are incomplete and need a further character. F31.0, F31.2, F31.4, F31.5, F31.81, F31.89 and F31.9 are complete as written.

Which CPT codes are billed with bipolar disorder?

90791 for the diagnostic evaluation, then 90832, 90834 or 90837 for individual psychotherapy by session length. Where a prescriber provides medication management and therapy in the same visit, the psychotherapy add-on codes 90833, 90836 or 90838 are used with an evaluation and management code.

Check a code with Afia — free

Codes on this page were verified against the CMS ICD-10-CM code sets for FY2026 and FY2027 (FY2027 effective 1 October 2026). Last reviewed 19 September 2026. Verify against the current official code set before submitting.