NOS is a regulatory phrase used to ensure that doctors are treating things and billing for things “by the book.” NOS means Not Otherwise Specified. Huh? Let’s start at the beginning.
Bipolar disorder is a treatable mental illness that causes extreme mood swings. There are four types in official lingo: I, II, NOS (Not Otherwise Specified), and cyclothymia. The NOS type refers to symptoms that do not meet the criteria for bipolar I or II. The symptoms are intense and represent an obvious change from your normal mood and behavior, but they may not last long enough or you may not have enough of them to qualify as bipolar I or II.
Talk to your doctor about any symptoms you are having that represent a change in mood or behavior.