What Is Bipolar Disorder Not Otherwise Specified (NOS)?

A diagnosis suggestive rather than indicative of bipolarity

Young woman reclining on couch, psychologist looking at her in background.
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Bipolar disorder not otherwise (NOS) is one of those psychiatric terms that can provide more confusion than clarity to the person being diagnosed. Like schizoaffective disorder (a condition which falls somewhere in between schizophrenia and bipolar disorder), bipolar disorder NOS is both kinds of a diagnosis and kind of not.

Understanding Bipolar Disorder Not Otherwise Specified

Bipolar disorder NOS is more of a catch-all category than an actual type of bipolar disorder.

Your doctor may use the classification to document symptoms which are consistent with bipolar disorder but fall short of the criteria needed to make a definitive diagnosis.

In general, NOS is most commonly used when a mood disorder is characterized by depression alternating with short episodes of hypomania (a milder form of mania). Oftentimes, the mood swings are rapid, occurring within days of each other. By and large, children and adolescents are most frequently diagnosed with NOS insofar as theirs will likely be the first visit with no previous history of mood dysfunction.

From a psychiatric standpoint, bipolar NOS is taken just as seriously as any other form of mood disorder. At its very heart, it presumes that there is a problem and that it will be likely be definitively diagnosed in the future. By assigning the NOS diagnosis now, the person will be less likely to "slip through the cracks" should another mood event occur.

Diagnostic Criteria for Bipolar Disorder NOS

There are no specific criteria as to when a doctor should make a bipolar NOS diagnosis. With that being said, the Diagnostic and Statistical Manual of Mental Disorders (DSM) issued by the American Psychiatric Association does provide examples as to when it may be appropriate:

  • The person has experienced alternating manic or depressive symptoms, but the episodes are too short to meet the criteria for inclusion.
  • The person has experienced both hypomania and depression, but the episodes are too short to qualify as a cyclothymic disorder.
  • The person may have had multiple episodes of hypomania but no depressive episode.
  • The person has had a manic or mixed episode after having been previously diagnosed with either schizophrenia or a psychotic episode.
  • The person meets the criteria for bipolar disorder, but the doctor is concerned that the symptoms may be caused by recreational drugs, alcohol, or a neurological disorder.

Treatment of Bipolar Disorder NOS

There is no established treatment plan for bipolar disorder NOS. As such, treatment is largely based on a doctor's clinical experience and the appropriate use of medications (including mood stabilizers and antipsychotics) and psychotherapy.

In the event that substance abuse or an undiagnosed condition is suspected, further investigations may be ordered. These may include a drug screen, neurological exams, or other diagnostic tests used to pinpoint infection, injury, or malignancy.

A Word From Verywell

While the NOS diagnosis can be frustrating for those looking for a definitive cause, it's important to remember that it's often better to monitor the condition than rush into treatment and expose a person to drugs he or she may not need.

We have seen the consequences of this when a bipolar disorder is misdiagnosed as depression. When this happens, a person may be wrongly treated with antidepressants and flipped into a manic state.

In the end, when it comes to an inconclusive bipolar diagnosis, it is always better to take a conservative approach until you have a better idea of what you're dealing with.


Towbin, K.; Axelson, D.; Leibenluft, E.; and Birmaher, B. "Differentiating Bipolar Disorder–Not Otherwise Specified and Severe Mood Dysregulation." Journal of the Academy of Child and Adolescent Psychiatry. 2013; 52(5):466-481.