Sleep deprivation
The specific causal relationships between sleep loss and effects on psychiatric disorders have been most extensively studied in patients with mood disorders. Shifts into mania in bipolar patients are often preceded by periods of insomnia, and sleep deprivation has been shown to induce a manic state in about 30% of patients. Sleep deprivation may represent a final common pathway in the genesis of mania, and manic patients usually have a continuous reduced need for sleep.