Bipolar Disorder Not Otherwise Specified (NOS)

When a diagnosis is suggestive rather than indicative of bipolarity

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Bipolar disorder not otherwise specified (NOS) is one of those psychiatric terms that can cause more confusion than clarity, especially to the person being diagnosed. Bipolar disorder NOS is usually diagnosed when a patient shows some symptoms of bipolar disorder but doesn't necessarily meet all the criteria as outlined in the Diagnostic and Statistical Manual of Mental Disorders.

The term bipolar disorder NOS was used in the fourth edition of the DSM (DSM-IV); however, the DSM-5 actually uses the terms "unspecified bipolar disorder" or "specified bipolar disorder" to diagnose conditions that were previously called bipolar disorder NOS.

Like schizoaffective disorder, a condition that falls somewhere in between schizophrenia and bipolar disorder, bipolar disorder NOS may suggest you are at risk of eventually developing bipolar disorder.

What Not Otherwise Specified Means

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 ascribed 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 as they will be least likely to have a previous history of mood dysfunction.

From a psychiatric standpoint, bipolar disorder NOS is taken just as seriously as any other form of mood disorder. It presumes that there is a concern and that it likely will be more 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 episode occur.

Still, there remains contention in the psychiatric community as to whether bipolar disorder NOS is a valid diagnosis or if it may lead to the premature treatment or over-treatment of an otherwise presumptive illness.

Unspecified vs. Specified Bipolar Disorder

As mentioned, the American Psychiatric Association (APA) prefers the terms unspecified or specified for bipolar disorder to better reflect the uncertainty of the diagnoses. (The terms unspecified and specified are also used for types of depressive disorders in the DSM-5).

Specified bipolar disorder may be diagnosed when a person displays specific symptoms of bipolar (such as manic and/or depressive episodes), but the full criteria for those symptoms aren't met. Unspecified bipolar may be the diagnosis when a person's symptoms resemble the symptoms of bipolar disorder, but they can't be labeled as bipolar symptoms for certain.

Diagnostic Criteria

The Diagnostic and Statistical Manual of Mental Disorders (DSM) issued by the APA does provide examples as to when it may be appropriate to diagnose bipolar disorder NOS (or as they call it, specified/unspecified):

  • 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.

Differential Diagnoses

Any informed diagnosis of bipolar disorder NOS would involve a review of all other possible causes.

In the event that substance abuse or an undiagnosed medical condition is suspected, further investigations may be ordered, including blood tests, a drug screen, neurological imaging, or other diagnostic techniques to identify an infection, injury, or malignancy.

The doctor should also consider other psychiatric conditions that closely mimic bipolar disorder NOS. One such example is a severe mood dysregulation (SMD), a condition seen in children and adolescents which is characterized by a persistently irritable or angry mood accompanied by frequent temper outbursts that are disproportionate to the situation.

Unlike bipolar disorder NOS, SMD does not have distinct manic episodes but is rather defined by the persistence of irritability and temper. Current research strongly suggests that SMD is, in fact, not a form of bipolar disorder and that children with SMD are not at high risk of developing bipolar disorder as they get older.

By contrast, bipolar NOS is commonly regarded as a precursor to either bipolar I or bipolar II disorder.

Treatment

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

Currently, there is little evidence on how to appropriately treat bipolar disorder NOS or whether treatment offers any benefit compared to a watch-and-wait approach.

Most experts still agree that psychotherapy can be beneficial to anyone deemed at risk of developing full-blown symptoms of bipolar disorder, ideally starting early.

A Word From Verywell

While the NOS diagnosis can be frustrating for anyone looking for a definitive cause of their mood symptoms, it's important to remember that it is often better to monitor a condition than rush into treatment that could expose a person to drugs they may not need.

It is a situation commonly seen when someone with bipolar disorder is misdiagnosed with depression. When this happens, the person may be wrongly treated with antidepressants and experience an acute manic episode.

In the end, when it comes to offering a bipolar diagnosis, it is always better to take a conservative approach until you have a clearer sense of what your condition is.

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4 Sources
Verywell Mind uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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  2. American Psychiatric Association: Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition. Arlington, VA: American Psychiatric Association, 2013.

  3. National Alliance on Mental Illness. Bipolar disorder.

  4. Swartz HA, Swanson J. Psychotherapy for Bipolar Disorder in Adults: A Review of the EvidenceFocus (Am Psychiatr Publ). 2014;12(3):251–266. doi:10.1176/appi.focus.12.3.251

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