Atypical bipolar disorder is barely spoken of, mainly because it does not have any defining features. The Diagnostic and Statistical Manual of Mental Disorders, published by the American Psychiatric Association, includes a category for NOS, that is, not as specified. Some forms of bipolar can be difficult to diagnose, as they don't fit into any standard pattern of behaviors. Here are the four signs that the APA classifies as indicating atypical bipolar disorder.
1.) Rapid Mood Fluctuations
Normally, a manic or depressive mood has to last for days to classify as bipolar disorder, but in some cases manic symptoms don't meet the minimal duration considered for a diagnosis. Of course, everyone doesn't fit into a nice little box, so different people with bipolar disorder will experience different severity and duration of their symptoms.
2.) Recurrent Hypomanic Episodes
Like a pendulum, when someone with bipolar disorder has a mood swing one way, they will swing back in the other direction. Usually this means a hypomanic phase will result in mild to severe depression. In atypical bipolar disorder, a person can go from a hypomanic phase to normal, and back again, skipping the depressive phase.
3.) Clouded Data
Sometimes drugs or medications can mimic the effects of bipolar disorder. For example, methamphetamines can mimic the appearance of mania, though the effects are the temporary side effect of a drug. If a psychiatrist is not sure whether the bipolar is caused by drugs, they will classify it as atypical.
4.) Co-existing Illnesses
Mental disorders are linked, so it can sometimes be difficult to tell which one someone has. Sometimes a person will show symptoms of schizophrenia and bipolar disorder together, making it hard to determine whether the person is schizophrenic or manic depressive. In instances where disorders are stacked on top of one another, someone can be classified as having atypical bipolar disorder.