Bipolar NOS: What It Means
What bipolar NOS (not otherwise specified) means, how it differs from other bipolar diagnoses, its symptoms, and how it is treated.
Clinically reviewed by Dr. Ponlawat Pitsuwan, Physician and Addiction Medicine Specialist, Phuket Island Rehab.
Bipolar NOS (bipolar disorder not otherwise specified) is a diagnosis that was used for people who have significant symptoms of bipolar disorder, involving abnormal shifts in mood, energy, and activity, but whose symptoms do not fully fit the specific criteria for the main types of bipolar disorder (such as bipolar I or bipolar II). In other words, it was a category for bipolar-type mood problems that are real and impairing but do not neatly match a defined type, for example because the mood episodes are shorter, milder, or fewer than required for a specific diagnosis. The term NOS (not otherwise specified) comes from an older diagnostic system; in the current system it has largely been replaced by terms such as other specified bipolar and related disorder or unspecified bipolar and related disorder, which serve a similar purpose. Bipolar NOS is not a lesser or less real condition; it still involves genuine mood symptoms that can significantly affect a person’s life and that deserve proper assessment and treatment. It is treated much like other forms of bipolar disorder, typically with a combination of medication (such as mood stabilisers) and psychological therapy and support. If you or someone you know has bipolar-type mood symptoms, seeking professional assessment and help is important, and effective treatment is available.
What does bipolar NOS mean?
Bipolar NOS stands for bipolar disorder not otherwise specified. It is a diagnosis that was used for people who have significant symptoms of bipolar disorder, but whose symptoms do not fully fit the specific criteria for the main, defined types of bipolar disorder. To understand it, it helps to know that bipolar disorder is a mental health condition involving abnormal shifts in mood, energy, and activity levels, with periods of unusually elevated or irritable mood and energy (manic or hypomanic episodes) and often periods of depression. There are recognised types, such as bipolar I disorder (involving full manic episodes) and bipolar II disorder (involving hypomanic episodes and depression), each with specific criteria. Bipolar NOS was the category used when a person clearly had bipolar-type mood problems that were real and impairing, but which did not neatly meet the full criteria for one of these specific types, for example because the mood episodes were shorter, milder, less frequent, or otherwise did not exactly match the defined patterns.
This article explains what bipolar NOS means, how it differs from other bipolar diagnoses, its symptoms, and how it is treated. The central message is that bipolar NOS was a diagnostic category for genuine bipolar-type mood symptoms that do not fully fit a specific type of bipolar disorder, that it is not a lesser or less real condition (the symptoms are real and can significantly affect a person’s life), and that it deserves and responds to proper assessment and treatment, much like other forms of bipolar disorder. It is also important to note that the term NOS comes from an older diagnostic system and has largely been replaced in the current system by terms such as other specified or unspecified bipolar and related disorder, which serve a similar purpose. Understanding what bipolar NOS means can help people make sense of such a diagnosis and appreciate that it points to a real, treatable condition. If you or someone you know has bipolar-type mood symptoms, seeking professional help is important, and effective treatment is available.
Bipolar NOS and the other bipolar diagnoses
To understand bipolar NOS, it helps to see how it fits alongside the other bipolar diagnoses. Bipolar disorder is not a single, uniform condition but a spectrum, and diagnostic systems define several types based on the pattern and severity of mood episodes. Bipolar I disorder is characterised by at least one full manic episode (a period of abnormally elevated, expansive, or irritable mood and increased energy, severe enough to cause significant problems or require hospitalisation), often with depressive episodes as well. Bipolar II disorder is characterised by a pattern of hypomanic episodes (a less severe form of elevated mood and energy) and depressive episodes, without full mania. There is also cyclothymic disorder (cyclothymia), involving numerous periods of hypomanic and depressive symptoms over a long time that do not meet the full criteria for hypomanic or depressive episodes. Each of these has specific diagnostic criteria.
Bipolar NOS was the category used when a person had significant bipolar-type mood symptoms that did not fully meet the criteria for any of these specific types. This could be for various reasons: the mood episodes might be too short in duration, too few in number, or not quite severe enough to meet the full criteria, or the pattern might not exactly match a defined type, even though the person clearly had real and impairing bipolar-type mood problems. In this way, bipolar NOS acted as a category for genuine bipolar spectrum conditions that fell outside the neatly defined types. In the current diagnostic system (the DSM-5), the term bipolar NOS has largely been replaced by other specified bipolar and related disorder (used when the clinician specifies why the presentation does not meet a specific type) and unspecified bipolar and related disorder (used when the reason is not specified or there is not enough information), which serve essentially the same purpose. So bipolar NOS, and its current equivalents, capture real bipolar-type conditions that do not fit the main defined types. Importantly, this does not make them less real or less deserving of treatment; it simply reflects that mental health conditions do not always fit neatly into defined categories, and that a person’s genuine symptoms still need proper assessment and care.
| Diagnosis | Brief description |
|---|---|
| Bipolar I | At least one full manic episode; often depression too |
| Bipolar II | Hypomanic episodes and depression; no full mania |
| Cyclothymia | Long-standing milder ups and downs |
| Bipolar NOS | Real bipolar-type symptoms not fitting a specific type |
| Current terms | Other specified / unspecified bipolar and related disorder |
| Key point | Still a real, impairing, and treatable condition |
Symptoms and treatment
The symptoms of bipolar NOS are essentially the symptoms of bipolar disorder, involving abnormal shifts in mood, energy, and activity, though in a pattern that does not fully fit a specific type. A person may experience periods of elevated or irritable mood and increased energy, which can include feeling unusually euphoric, energetic, or irritable, needing less sleep, talking rapidly, having racing thoughts, feeling grandiose or overconfident, being easily distracted, and engaging in impulsive or risky behaviour, features of manic or hypomanic states, though in bipolar NOS these may be shorter, milder, or otherwise not fully meeting the criteria for a defined episode. A person may also experience periods of depression, with low mood, loss of interest or pleasure, changes in sleep and appetite, low energy, difficulty concentrating, feelings of worthlessness or hopelessness, and, importantly, sometimes thoughts of suicide. The specific pattern varies between individuals. These symptoms, even if they do not fit a defined type, can significantly affect a person’s mood, functioning, relationships, and life, and can be distressing and impairing, which is why proper assessment and treatment matter.
Bipolar NOS is treated much like other forms of bipolar disorder, with treatment tailored to the individual’s symptoms and needs. Treatment typically involves a combination of medication and psychological therapy and support. Medications used in bipolar disorder include mood stabilisers and certain other medications, which help to stabilise mood and manage manic, hypomanic, and depressive symptoms; the specific medication is chosen by a doctor based on the person’s presentation. Psychological therapies, such as cognitive behavioural therapy and other approaches, help a person understand and manage their condition, recognise and cope with mood changes, develop strategies to stay well, and address any associated difficulties. Education about the condition, support, help with lifestyle factors (such as sleep and stress management, which can affect mood), and support for family are also valuable. Treating any co-occurring conditions, including substance use problems (which can co-occur with bipolar disorder and can worsen mood symptoms), is important too. Because bipolar-type conditions are usually long-term, ongoing management and support help a person stay well over time. The key messages are that bipolar NOS means genuine bipolar-type mood symptoms that do not fully fit a specific type, that it is a real, impairing, and treatable condition (now often termed other specified or unspecified bipolar and related disorder), and that it is treated, much like other bipolar disorders, with medication, therapy, and support. If you or someone you know has bipolar-type mood symptoms, seeking professional assessment and help is important, and effective treatment is available.
Summary
Bipolar NOS (bipolar disorder not otherwise specified) is a diagnosis that was used for people who have significant symptoms of bipolar disorder, involving abnormal shifts in mood, energy, and activity, but whose symptoms do not fully fit the specific criteria for the main types of bipolar disorder (such as bipolar I or bipolar II). In other words, it was a category for bipolar-type mood problems that are real and impairing but do not neatly match a defined type, for example because the mood episodes are shorter, milder, or fewer than required for a specific diagnosis. The term NOS (not otherwise specified) comes from an older diagnostic system; in the current system it has largely been replaced by terms such as other specified bipolar and related disorder or unspecified bipolar and related disorder, which serve a similar purpose. Bipolar NOS is not a lesser or less real condition; it still involves genuine mood symptoms that can significantly affect a person’s life and that deserve proper assessment and treatment. It is treated much like other forms of bipolar disorder, typically with a combination of medication (such as mood stabilisers) and psychological therapy and support. If you or someone you know has bipolar-type mood symptoms, seeking professional assessment and help is important, and effective treatment is available.
As Dr. Ponlawat Pitsuwan, addiction medicine specialist at Phuket Island Rehab, puts it, “Patients are sometimes unsettled to be told they have bipolar NOS, as if it means the doctors are not sure or it is not a proper diagnosis. I reassure them that it is a real, recognised way of saying: your mood swings are genuine and significant, but they do not tidy up into the exact box of bipolar I or II. Mood does not always read the textbook. The newer wording, other specified or unspecified bipolar and related disorder, means the same thing. What matters is that the symptoms are real, they affect your life, and they respond to the same kinds of treatment, mood stabilisers, therapy, good sleep, support. So it is not a lesser condition, it is a treatable one, and getting properly assessed is the important step.”
Frequently asked questions
What is bipolar NOS?
Bipolar NOS (bipolar disorder not otherwise specified) is a diagnosis used for people who have significant symptoms of bipolar disorder, involving abnormal shifts in mood, energy, and activity, but whose symptoms do not fully fit the specific criteria for the main defined types of bipolar disorder, such as bipolar I or bipolar II. It was the category used when a person clearly had bipolar-type mood problems that were real and impairing but did not neatly meet the full criteria for a specific type, for example because their mood episodes were shorter, milder, less frequent, or otherwise did not exactly match the defined patterns. The term NOS comes from an older diagnostic system; in the current system (DSM-5), it has largely been replaced by terms such as other specified bipolar and related disorder and unspecified bipolar and related disorder, which serve a similar purpose. Importantly, bipolar NOS is not a lesser or less real condition; the symptoms are genuine and can significantly affect a person’s mood, functioning, and life, and they deserve proper assessment and treatment. It reflects the reality that mental health conditions do not always fit neatly into defined categories. Bipolar NOS is treated much like other forms of bipolar disorder, and effective treatment is available. So it is a real, treatable bipolar-spectrum condition.
How is bipolar NOS different from bipolar I or II?
Bipolar NOS differs from bipolar I and bipolar II in that it is used when a person’s bipolar-type symptoms do not fully meet the specific criteria for those defined types. Bipolar I disorder is characterised by at least one full manic episode (a period of abnormally elevated or irritable mood and increased energy, severe enough to cause significant problems), often with depressive episodes. Bipolar II disorder is characterised by a pattern of hypomanic episodes (a less severe form of elevated mood and energy) and depressive episodes, without full mania. Both have specific diagnostic criteria regarding the type, severity, and duration of mood episodes. Bipolar NOS was the category used when a person had genuine, significant bipolar-type mood symptoms that did not fully meet the criteria for bipolar I, bipolar II, or other defined types, perhaps because the episodes were too short, too few, or not quite severe enough, or the pattern did not exactly match. So the main difference is that bipolar I and II are specific, defined types with set criteria, while bipolar NOS (now often called other specified or unspecified bipolar and related disorder) covers real bipolar-spectrum conditions that fall outside those neatly defined types. This does not make bipolar NOS less real or less serious; it simply reflects a presentation that does not fit a specific category. All are treated similarly, with medication, therapy, and support, and effective treatment is available for each.
Is bipolar NOS a real or serious condition?
Yes, bipolar NOS is a real and can be a serious condition. Although the name (not otherwise specified) might make it sound vague or less significant, bipolar NOS refers to genuine bipolar-type mood symptoms that are real and impairing, even though they do not fully fit the criteria for a specific defined type of bipolar disorder. The symptoms, involving abnormal shifts in mood, energy, and activity, with periods of elevated or irritable mood and often periods of depression, can significantly affect a person’s mood, functioning, relationships, and life, and can be distressing and impairing. Depression that occurs as part of the condition can also carry a risk of suicidal thoughts, which is serious. So bipolar NOS is not a lesser or less real condition than the specific types of bipolar disorder; it simply describes a bipolar-spectrum condition that does not neatly match a defined type. It deserves proper assessment and treatment just as much as the specific types. The reassuring point is that, like other forms of bipolar disorder, bipolar NOS is treatable, typically with a combination of medication, therapy, and support, and with proper treatment, people can manage their condition and stay well. So if you or someone you know has been given this diagnosis, it should be taken seriously as a real condition, and appropriate treatment and support should be sought, which are effective.
What are the symptoms of bipolar NOS?
The symptoms of bipolar NOS are essentially those of bipolar disorder, involving abnormal shifts in mood, energy, and activity, but in a pattern that does not fully fit a specific type. A person may experience periods of elevated or irritable mood and increased energy, which can include feeling unusually euphoric, energetic, or irritable, needing less sleep, talking rapidly, having racing thoughts, feeling grandiose or overconfident, being easily distracted, and engaging in impulsive or risky behaviour, features of manic or hypomanic states, though in bipolar NOS these may be shorter, milder, or otherwise not fully meeting the criteria for a defined episode. A person may also experience periods of depression, with low mood, loss of interest or pleasure, changes in sleep and appetite, low energy, difficulty concentrating, feelings of worthlessness or hopelessness, and sometimes thoughts of suicide. The specific pattern and balance of symptoms vary between individuals. Even though these symptoms may not fit a defined type, they can significantly affect a person’s mood, functioning, relationships, and life, and can be distressing and impairing. Because the symptoms overlap with those of other conditions and can be complex, proper assessment by a mental health professional is important to understand what is going on and guide treatment. If you or someone you know is experiencing these kinds of mood symptoms, seeking professional assessment is worthwhile, and effective treatment is available for bipolar-spectrum conditions, including bipolar NOS.
How is bipolar NOS treated?
Bipolar NOS is treated much like other forms of bipolar disorder, with treatment tailored to the individual’s symptoms and needs, and typically involving a combination of medication and psychological therapy and support. Medications used in bipolar disorder include mood stabilisers and certain other medications, which help to stabilise mood and manage manic, hypomanic, and depressive symptoms; the specific medication is chosen by a doctor based on the person’s presentation, and finding the right medication or combination can take some adjustment. Psychological therapies, such as cognitive behavioural therapy and other approaches, help a person understand and manage their condition, recognise and cope with mood changes, develop strategies to stay well, and address associated difficulties. Education about the condition, support, and help with lifestyle factors such as sleep and stress management (which can affect mood) are also valuable, as is support for family. Treating any co-occurring conditions, including substance use problems, which can co-occur with bipolar disorder and worsen mood symptoms, is important. Because bipolar-type conditions are usually long-term, ongoing management and support help a person stay well over time and reduce the risk of relapse. With appropriate treatment, people with bipolar NOS can manage their condition, stabilise their mood, and lead fulfilling lives. So although it does not fit a specific defined type, bipolar NOS responds to the same effective treatments as other bipolar disorders. If you or someone you know has this condition, seeking and engaging with treatment is important and effective.
Why do diagnoses like NOS exist?
Diagnoses like NOS (not otherwise specified), and their current equivalents such as other specified and unspecified disorders, exist because mental health conditions do not always fit neatly into the specific, defined categories that diagnostic systems set out. Diagnostic systems define specific disorders (such as bipolar I and bipolar II) with set criteria, but in reality people’s symptoms are varied and do not always match these criteria exactly, even when the person clearly has a genuine, significant, and impairing condition. NOS and similar categories exist to capture these real conditions that fall outside the defined types, ensuring that people whose symptoms do not neatly fit a specific diagnosis can still be recognised as having a real condition and can receive appropriate assessment, treatment, and support, rather than being left without a diagnosis. In the case of bipolar NOS, this meant recognising genuine bipolar-type mood problems that did not fully meet the criteria for a specific bipolar type. In the current system, terms like other specified bipolar and related disorder (where the clinician notes why it does not fit a specific type) and unspecified bipolar and related disorder serve this purpose. So these categories are a practical and important part of diagnosis, reflecting the reality that human conditions are diverse and do not always fit neat boxes, and ensuring that people still get the recognition and care they need. Their existence does not mean the conditions are less real; it means the diagnostic system can accommodate the full range of genuine presentations.
Sources
National Institute of Mental Health (NIMH). Bipolar Disorder. https://www.nimh.nih.gov/health/topics/bipolar-disorder
American Psychiatric Association (APA). Bipolar and Related Disorders. https://www.psychiatry.org/patients-families/bipolar-disorders
National Health Service (NHS). Bipolar Disorder. https://www.nhs.uk/mental-health/conditions/bipolar-disorder/
National Library of Medicine (MedlinePlus). Bipolar Disorder. https://medlineplus.gov/bipolardisorder.html
World Health Organization (WHO). Bipolar Disorder. https://www.who.int/news-room/fact-sheets/detail/bipolar-disorder
Substance Abuse and Mental Health Services Administration (SAMHSA). Mental Health and Co-occurring Conditions. https://www.samhsa.gov/
Bipolar NOS — key entities and related terms
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