Sleep loss: a preventable cause of mania and other excited states.

Experiments show that sleep loss can trigger symptoms of mania or hypomania in certain bipolar patients. Exposure to light might have a similar effect in some patients with seasonal forms of bipolar illness. Attention to the possible role of sleep loss and light as triggering factors in the pathogenesis of mania may help clinicians and patients to identify some of the factors that influence the natural course of the bipolar illness and to devise strategies for its prevention and treatment.