Orexin Agonists — Two Steps Forward, One Step Back

In 1880, Gélineau described a rare syndrome characterized by severe sleepiness with attacks of sleep at inappropriate times during the day and cataplexy, a sudden loss of muscle tone related to emotion; he called this syndrome narcolepsy.1 Patients with narcolepsy also have visual dreamlike hallucinations and sleep paralysis (both characteristic of rapid-eye-movement [REM] sleep), the presence of the HLA-DQB1*06:02 variant, and disturbed nocturnal sleep. This "classic" form of narcolepsy is now called narcolepsy type 1. Narcolepsy type 2 is characterized by sleepiness, aberrant REM periods at the onset of sleep, and no cataplexy. In another syndrome, idiopathic hypersomnia, patients are . . .