F31.31 – Bipolar disorder, current episode depressed, mild

F31.31 – Bipolar disorder, current episode depressed, mild

Learn about the ICD F31.31, identifying mild depressive episodes in bipolar disorder through this guide.

By Matt Olivares on Aug 8, 2025.

Fact Checked by Karina Jimenea.

Use Code

F31.31 diagnosis code: Bipolar disorder, current episode depressed, mild

  • F31.31 is an ICD-10-CM code used to diagnose a current episode of mild depression within bipolar disorder.
  • This indicates that the individual is in a depressive phase, with noticeable symptoms but not severe enough to cause marked impairment in social or occupational functioning.
  • The code requires a history of at least one manic or hypomanic episode, characterizing the bipolar disorder diagnosis.
  • The 'mild' tag signifies that the symptoms, while identified, are not significantly disrupting the patient's daily life. So, don't use it for those with major depressive episodes.
  • The patient must be confirmed to have bipolar disorder. This can't be used if the patient isn't, even if they have mild/major depressive disorder.

Is F31.31 billable?

Yes, F31.31 is a billable code. It can be used to specify a diagnosis for reimbursement purposes. Furthermore, it validates the services provided by healthcare professionals, confirming the medical necessity for the treatment provided.

Clinical information

  • Bipolar disorder is characterized by periods of dramatically elevated mood (mania or hypomania) and drastically low mood (depression). It is a manic-depressive illness.
  • A person diagnosed with F31.31 is currently in a depressive phase classified as mild.
  • Symptoms during this phase may include sadness, decreased energy, minor sleep disturbances, and reduced interest in activities they usually enjoy.
  • While distressing, these symptoms are manageable and don't significantly interfere with the person's daily routine.
  • Ongoing treatment, typically a combination of medications and psychotherapy, is necessary to manage bipolar disorder.
  • As mentioned earlier, this is only for mild cases. If you're wondering if you can use this for mild or moderate severity, please note that F31.32 is for moderate cases. F31.4 and F31.5 are for the current episode depressed, severe (the former is for those without psychotic features, the latter with psychotic features).
  • This cannot be used for current episode manic, severe (or moderate or mild) cases.

Synonyms include

  • Mild depressive episode in bipolar disorder
  • Bipolar II disorder, current episode depressed, mild
  • Mild bipolar depression
  • Bipolar affective disorder, current episode depression, mild
  • Bipolar disorder in partial remission, most recent episode depressed
  • Disorder bipolar type depressive

Popular search terms for this ICD 10 code

  • F31.31 ICD-10 code
  • ICD-10 F31.31
  • F31.31 diagnosis code
  • ICD-10 code for bipolar disorder current episode depressed mild

Other ICD-10 codes commonly used for bipolar disorder

  • F31.11 - Bipolar disorder, current episode manic without psychotic features, moderate
  • F31.73 - Bipolar disorder, in partial remission, most recent episode manic
  • F31.4 - Bipolar disorder, current episode depressed, severe, without psychotic features
  • F31.6 - Bipolar disorder, current episode mixed
  • F31.5 - Bipolar disorder, current episode depressed, severe, without psychotic features
  • F31.2 - Bipolar disorder, current episode manic severe with psychotic features
  • F31.9 - Bipolar disorder, unspecified
  • F31.81 - Bipolar II disorder

Commonly asked questions

Yes, without proper management, mild depressive episodes in bipolar disorder can potentially escalate in severity.

Treatments typically involve medications like mood stabilizers, antidepressants, and sometimes psychotherapy, including cognitive behavioral therapy or interpersonal and social rhythm therapy.

Yes, maintaining a regular sleep schedule, eating a healthy diet, regular exercise, and avoiding alcohol, caffeine, and illicit substances can significantly aid in managing bipolar disorder.

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