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Is Bipolar Disorder Not Otherwise Specified (NOS) Really a Bipolar Illness?
Blogger Natasha Tracy explores the grey area of bipolar disorder diagnosis.
When diagnosing bipolar disorder, a psychiatrist assesses previous mood episodes. These mood episodes must reach the criteria for major depression and either mania or hypomania in order to warrant a diagnosis of bipolar disorder I or bipolar disorder II.
However, it is understood in diagnostic circles that sometimes bipolar disorder can present with symptoms outside the norm and yet still be classified as bipolar disorder. This is what the diagnosis of bipolar disorder not otherwise specified (NOS) is designed to address. Bipolar disorder NOS is a bipolar condition that does not neatly fit into the symptomology of bipolar I or bipolar II.
I would guess that different psychiatrists would use the NOS label differently, but one study looking at the comparison of bipolar disorder NOS to major depression and traditional bipolar defined it as a mood disorder wherein the person suffers from major depressive episodes and recurrent 1-3 day hypomanias.
Is Bipolar NOS Really Different From Depression?
According to the above definition, yes, it is. Bipolar NOS separates itself from major depressive disorder in symptomology, personality traits and comorbidities and shows that bipolar NOS is generally more like bipolar disorder I/II than it is like unipolar depression.
Specifically, bipolar NOS scores higher in the following measures when compared to unipolar depression:
- melancholic depression (although not as high as bipolar disorder)
- social phobia (as high as bipolar disorder)
- obsessive compulsive disorder (as high as bipolar disorder)
- alcohol dependence (as high as bipolar disorder)
- cannabis dependence (as high as bipolar disorder)
- severity on depression, hypomania and biphasic scales than depression although less so than bipolar 1 or 2
From a personality perspective, bipolar NOS shows differences from unipolar depression, scoring higher in the areas of:
- being a loner (as high as bipolar disorder)
- being impulsive (even more than bipolar disorder)
- being easily angered (not as high as bipolar disorder)
- obsessive-compulsive personality disorder traits (not as high as bipolar disorder)
- borderline personality disorder traits (not as high as bipolar disorder)
- self-transcendence (bettering the self; as high as bipolar disorder)
So although bipolar disorder NOS may not fit squarely into the bipolar diagnostic categories, it still appears to be part of the bipolar spectrum and a valid bipolar diagnosis.
The authors of the above study, though, do note that because this is a milder form of bipolar disorder, it may or may not respond as well to mood stabilizers as traditional bipolar disorder.
For all the details, please see Bipolar Disorder not Otherwise Specified: Comparison with Bipolar Disorder I/II and Major Depression.