A. Manic Disorder: Now that pharmacological treatment has become widespread, the complete natural history of a manic episode is seldom observed. Speed of onset, severity, and duration of the manic episode vary greatly in different individuals, depending, apparently, in part on genetic and other factors not clearly understood. Descriptions of past manic episodes are the best source of information about future episodes. Predictions about the future course of a patient experiencing a first manic episode are necessarily vague. In many individuals, the onset of the manic episode will be abrupt, occurring over a period of days or in some cases hours, and classically occurring in the early morning hours, first noted either as early morning awakening or inability to fall asleep. Other individuals experience a more protracted onset over a period of weeks. Increases in psychomotor activity, increased energy, and elevated mood are the most common early signs, with manic speech and thought disorder occurring later if at all. Not all individuals pass through the classical sequence of events or progress to the same level of severity. There have been reports of manic individuals who have no complaints of sleep disturbance or obvious euphoria but who appear not to differ either in the natural course of the illness or in response to treatment.
In some cases manic episodes appear to be self-limiting within days, weeks, or months. The variables that account for the wide reported ranges make assessments based on anything other than the individual’s own past history unreliable. Chronic mania has been described and may remain stable at different levels of severity. Although lithium carbonate and the anticonvulsant agents carbamazepine, valproate, lamotrigine, gabapentin, and topiramate represent a dramatic advance in the treatment of bipolar disorders, 15-20% of manic patients respond inadequately to the medication and continue to present either episodically or chronically with classical signs of the disorder. Even with appropriate treatment, patients who present with rapidly alternating episodes of mania and depression or mixed states are more likely to remain ill for an extended period of time than are patients who are purely manic. Bipolar patients experiencing their first episode of depression have an approximately 20% chance of remaining depressed for at least 1 year, a rate comparable to that of individuals with pure depression. In subsequent episodes, the cumulative risk for development of chronic refractory depression rises to 30%.
B. Bipolar Disorder: Although bipolar illness has traditionally been associated with a relatively late age at onset, current evidence indicates a peak age of onset of between 20 and 25 years. Some surveys have indicated that premorbid symptomatology may start even earlier in adolescence and, more rarely, in early childhood. Onset after age 60 is rare and may reflect causation by an undiagnosed medical condition. Bipolar illness with onset during childhood or adolescence is commonly misdiagnosed, a fact that may reflect historical diagnostic bias or diagnostic confusion arising from normal physical and psychological developmental changes during this period. Differentiation of childhood bipolar disorder from attention-deficit disorder is particularly difficult.