New perspectives in the diagnosis and therapy of narcolepsy

Narcolepsy syndrome is a common, although often misdiagnosed, neurological disorder, whose clinical features are excessive daytime somnolence with sleep attacks, caplexy, sleep paralysis and hypnagogic hallucinations. The clinical manifestation have been interpreted as the expression of a sudden intrusion of dissociated REM phenomena in wakefulness. Sometimes the clinical manifestations may include only some of the symptoms: in particular, the cases in which the only symptom is excessive daytime somnolence may be difficult to diagnose. The etiopathogenesis of narcolepsy syndrome is still poorly understood. Recent experimental evidences suggest that a protein, called "orexin", which is supposed to play a role in the control mechanisms of both sleep and eating behaviour, is involved in its pathogenesis. The treatment of narcolepsy has been, up to now, exclusively symptomatic, and in some way empirical and unsatisfactory, especially regarding to daytime sleepiness. Recently, new pharmacological agents, acting on the serotoninergic and/or noradrenergic systems, allow a better control of the cataplectic attacks. The recent development of modafinil, a central nervous system stimulant, devoid of the serious side effects of amphetamines and other compounds, allows to hope in a better control of daytime somnolence and sleep attacks. The aim of the paper is to describe the recent advances in the diagnosis and treatment of narcolepsy.