Distinguishing between mania and acute agitation caused by another mental health problem or a medical disorder, medication side effects or a substance of abuse can be challenging. A careful history helps to clarify whether a person is experiencing mood changes fluctuating between depression and mania or hypomania. Laboratory tests and functional brain imaging studies are sometimes helpful for determining whether a neurologic or other medical disorder is causing symptoms of depressed mood or mania. Medical problems that sometimes manifest as mania or depression include thyroid disease, strokes (especially in the right frontal area of the brain), multiple sclerosis, and (rarely) seizure disorders. Chronic abuse of stimulants such as methamphetamine (‘speed’) and cocaine, marijuana and other drugs sometimes causes mood swings such as irritability or feelings of intense euphoria alternating with depressed mood.
It is sometimes difficult to diagnose bipolar disorder even after other psychiatric or medical problems have been excluded because of the great variability in symptoms of mania. For example, irritability, agitation and rapid and intense ‘swings’ in emotions often take place in individuals who chronically abuse drugs or alcohol, as well as in individuals who struggle with schizophrenia or severe personality disorders such as borderline personality disorder. The diagnosis of bipolar disorder is made more complicated by the fact that acutely manic individuals often experience auditory hallucinations, delusions, paranoia and grossly confused thinking, making it difficult to distinguish bipolar mania from symptoms of schizophrenia or other psychotic disorders especially when limited information is available about a patient’s history.