Lithium Treatment Of Kleine-Levin Syndrome An Advance For A Disorder Of Hypersomnolence

In 1925, Willi Kleine1 described a series of 5 patients with “periodic sleepiness” of diverse etiology. In 1936, Levin2 published additional cases with “a syndrome of periodic somnolence and morbid hunger.” The diagnosis of Kleine-Levin syndrome (KLS), according to the International Classification of Sleep Disorders–3 ,3 requires (1) recurring episodes, usually more than once a year and at least once every 18 months; (2) normal alertness, cognitive function, behavior, and mood between episodes; and (3) at least one of the following during episodes: cognitive dysfunction, altered perception, eating disorder (anorexia or hyperphagia), and disinhibited behavior (such as hypersexuality). Recent evidence suggests that KLS can be a lifelong disease.4 Early manifestation, combined with hypersexuality during symptomatic phases, seems to be a predictor for a long course of the disease, which can last from 1 to 27 years. Due to the lack of biological markers, diagnosis at first manifestation (mainly in the mid-20s) is difficult.