2026 ICD-10-CM Diagnosis Code F31.9Bipolar disorder, unspecified

ICD-10-CM Codes›F01–F99›F30-F39›F31

ICD-10-CM F31.9
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

F31.9 is a billable ICD-10-CM diagnosis code for bipolar disorder, unspecified. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026). Coders also document this condition as bipolar affective disorder, current episode manic. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Bipolar and related disorders.

Code Identity

ICD-10-CM Code
F31.9
Billable Status
Yes — Valid for Submission
Code Describes
Bipolar disorder, unspecified
Short Description
Bipolar disorder, unspecified
Same as the full description in the CMS dataset.
Parent Code
F31
Bipolar disorder

Code Classification

ChapterF01–F99Mental and behavioural disorders
SectionF30-F39Mood [affective] disorders
CategoryF31Bipolar disorder
This CodeF31.9Bipolar disorder, unspecified

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Bipolar affective disorder, current episode manic
  • Bipolar disorder
  • Bipolar disorder, most recent episode depression
  • Bipolar disorder, most recent episode manic
  • Bipolar I disorder
  • Bipolar I disorder, most recent episode depression
  • Severe bipolar disorder
  • Severe bipolar disorder with psychotic features
  • Severe bipolar I disorder

Tabular List NotesGuidance

Coding notes and annotation back-references applicable to this code.

Inclusion Terms

  • Manic depression

Index to Diseases and InjuriesGuidance

Alphabetical index entries that point to this code.

External Cause of Injuries IndexGuidance

References for this code in the External Cause of Injuries Index.

    • Disorder(of)
      • bipolar (I) (seasonal) (type 1)
    • Disorder(of)
      • bipolar (I) (seasonal) (type 1)
        • current (or most recent) episode
          • depressed
    • Disorder(of)
      • bipolar (I) (seasonal) (type 1)
        • current (or most recent) episode
          • manic
    • Manic depression

Clinical ClassificationClinical

AHRQ’s CCSR groups this code into broader clinical categories.

CCSR MBD003
Bipolar and related disorders
Default principal diagnosis: inpatient Yes · outpatient Yes

Clinical InformationClinical

  • Bipolar Disorder

    a major affective disorder marked by severe mood swings (manic or major depressive episodes) and a tendency to remission and recurrence.

Patient EducationClinical

Bipolar Disorder

Bipolar disorder is a mood disorder that can cause intense mood swings:

The full article covers:

  • What is bipolar disorder?
  • What are the types of bipolar disorder?
  • What causes bipolar disorder?
  • Who is at risk for bipolar disorder?
  • What are the symptoms of bipolar disorder?
  • How is bipolar disorder diagnosed?
  • What are the treatments for bipolar disorder?

Read the full article at MedlinePlus

Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.

Convert F31.9 to ICD-9-CMHistory

The closest ICD-9-CM equivalents under the General Equivalence Mappings.

ICD-9-CM
296.80 Bipolar disorder NOS
Approximate The match is approximate rather than exact.

Code HistoryHistory

FY 2016AddedAdded to the ICD-10-CM code setEffective October 1, 2015, the first year of ICD-10-CM.
FY 2017–2025No changes
FY 2026CurrentCurrent code set, no changesEffective October 1, 2025 through September 30, 2026.

Questions About F31.9Overview

Is F31.9 (Bipolar disorder) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report bipolar disorder, unspecified on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

What is the ICD-9 equivalent of F31.9?

Under the General Equivalence Mappings, bipolar disorder, unspecified converts to ICD-9-CM 296.80 (bipolar disorder NOS). The mapping is approximate, so confirm the match fits the documentation.

Footnotes

[1] Not chronic - A diagnosis code that does not fit the criteria for chronic condition (duration, ongoing medical treatment, and limitations) is considered not chronic. Some codes designated as not chronic are acute conditions. Other diagnosis codes that indicate a possible chronic condition, but for which the duration of the illness is not specified in the code description (i.e., we do not know the condition has lasted 12 months or longer) also are considered not chronic.