This is an updated version of the original Cochrane review published in Issue 2, 2009.
Kleine-Levin Syndrome (KLS) is a rare disorder which mainly affects adolescent men. It is characterized by recurrent episodes of hypersomnia, usually accompanied by hyperphagia, cognitive and mood disturbances, abnormal behavior such as hypersexuality, and signs of dysautonomia.
In 1990 the diagnostic criteria for Kleine-Levin Syndrome were modified in the International Classification of Sleep Disorders, where it was defined as a syndrome composed of recurring episodes of undue sleepiness lasting some days, which may or may not be associated with hyperphagia and abnormal behavior.
The etiology of Kleine-Levin Syndrome remains unknown and several treatment strategies have been used. Some medications have been reported to provide some benefit for the treatment of Kleine-Levin Syndrome patients, but because of the rarity of the condition no long-term follow-up therapies have yet been described.