L’objet de cet article est une présentation d’un cas clinique original dont les symptômes correspondent à une pathologie très particulière du fait de sa rareté, de son expression symptomatique et de son éthiopathogénie non élucidée, qu’est le syndrome de Kleine-Levin. Il s’agit d’un jeune patient âgé de 15 ans qui a présenté une modification brutale du comportement, en rupture avec l’état antérieur, avec une hypersomnie au premier plan, au décours d’une angine concomitante avec un choc émotionnel. Nous avons assisté à une régression spontanée et totale de la symptomatologie au bout de 12 jours, exception faite de la persistance d’une amnésie lacunaire. Quatre mois plus tard, au décours d’une ivresse aiguë, le patient a présenté un nouvel épisode similaire. Après une présentation sous forme d’une vignette clinique, nous aborderons la situation sous un angle plus psychopathologique, en nous posant la question d’un profil psychologique favorisant et des liens éventuels avec les troubles bipolaires.

The purpose of this article is to report an original clinical case whose symptoms suggest a very peculiar pathology, because of its rarity, symptomatic expression and unclear etiopathogenesis: the Kleine-Levin Syndrome (KLS). During the regression of tonsillitis concomitant with an emotional shock, the 15-year-old patient exhibited a dramatic change in behaviour, at odds with his previous state, and accompanied by hypersomnia and confusion, megaphagia, irritability, hypersexuality and mood disorders. We observed a spontaneous and total regression of the symptoms after 12 days, except for the incomplete amnesia that proved to be persistent. Four months later, further to an ethylic drunkenness, the patient presented with a new and similar episode. The patient benefited from no medicinal treatment, even in the course of hypersomnia episodes and asymptomatic periods. After a clinical presentation of this patient, we will consider this case study from a more psychopathological angle by questioning the existence of a facilitating psychological profile. The discovery of an IQ equal to 86 from the scores of WISC-IV, and the identification of constructive visual difficulties made us suspect neurological disorders, but these abnormalities were not found during the completion of the Rey Complex Figure Test. The personality profile issued from the scores at the MMPI-A assessment was ranked as barely significant (type 2–4): indeed, it showed nothing specific to this patient. Literature data show that most of the patients presenting with a KLS have been seen by a psychiatrist at the time of the disease and diagnosed as suffering from hysteria, or schizophrenia, or bipolar disorders… Because of diagnostic wanderings, some patients have, hence, received inappropriate treatments. One should pay close attention to this very rare syndrome, on the border between neurology and psychiatry, since its diagnosis is essentially based on clinical features, and carefully think about the implementation of a medicinal treatment. This unique case seems unable to support our working hypothesis about the identification of a particular psychological profile in the KLS, but the question of an underlying fragility is still worth considering. We personally think that, even though links between the KLS and bipolar disorders have been suggested, this disease has to be considered as a separate entity.