Drugs are widely used to treat depression, but often take weeks to work effectively. Sleep deprivation, however, has been shown to be effective immediately in approximately 60% of patients with major depressive disorders. Although widely-recognized as helpful, it is not always ideal because it can be uncomfortable for patients, and the effects are not long-lasting.During the 1970s, research verified the effectiveness of acute sleep deprivation for treating depression, particularly deprivation of rapid eye movement sleep, but the underlying brain mechanisms were not known.