Narcolepsy is a sleep disorder in which a person in an active waking state shifts abruptly into several minutes of REM sleep, usually with no warning at all. As REM is the sleep stage in which most dreaming occurs, the disorder may be thought of as a sudden intrusion of dreaming sleep into the consciousness of a person who was awake a moment earlier. In addition to excessive daytime sleepiness, the classic symptoms of narcolepsy include cataplexy, a dramatic and sudden loss of muscle tone, often accompanied by paralysis, that is usually brought on by a strong emotion like fear, surprise, anxiety, or even excessive laughter. As narcolepsy involves the onset of REM sleep, this is unsurprising, as REM sleep is usually accompanied by sleep paralysis, or the disinhibition of muscle movement that prevents us from acting out our dreams as they happen.
Narcoleptic episodes are also frequently accompanied by hypnagogic hallucinations, extremely vivid dreamlike images that occur at the onset of sleep, before a person is fully asleep. This little-known phenomenon is actually fairly common in people without sleep disorders, and provides a possible explanatory mechanism for such unusual phenomena as alien abduction experiences, among others. Disturbances of nighttime sleep, including nightmares, leg jerks, tossing and turning, and frequent awakening, are also very common in people with narcolepsy and may explain some of the daytime sleepiness associated with the disorder. Unrelenting daytime sleepiness is usually the ﬁrst symptom of the disorder noticed, and it leads to irresistible “sleep attacks,” also sometimes called microsleeps, which can last anywhere from thirty seconds or less to more than thirty minutes, and which can occur anytime, no matter how inappropriate. The sleep attacks can occur at work or social events, while eating, or even while driving or doing hazardous work with machinery.
Currently, no cure for narcolepsy is known, but both drug treatment and behavioral treatment have been found helpful. Drug treatment has usually consisted of amphetamines and similar stimulants, but in 1999 the Food and Drug Administration (FDA) approved a new drug, modaﬁnil (brand name Provigil), for treatment of narcolepsy. While also a stimulant, it is notably different chemically from amphetamines, and it is said to be far less likely to cause jitteriness and difﬁculty sleeping at night, as well as possessing some mood-enhancing effects. Antidepressant medications are sometimes prescribed as well, to reduce cataplexy and sleep paralysis. Medications only alleviate symptoms, however, while doing nothing to eliminate the underlying problem. Behavioral treatments focused on lifestyle change, such as adjusting sleep schedules, scheduling regular naptimes, and avoiding the excessive emotional stimulation that can trigger cataplexy, have also shown promise.
Ultimately, the prognosis for narcolepsy sufferers will improve further as the causes of the disorder become better understood. In 1999 a team of Stanford University researchers working with dogs identiﬁed a defective gene that appeared to cause the disorder. More recently, this ﬁnding has been extended to humans, providing both a possible etiology for the disorder and potential new directions in treatment. The Stanford team found that a small peptide, hypocretin, which naturally occurs in the brains of people without narcolepsy, was absent in every narcoleptic brain studied. The cells that manufacture hypocretin, of which a normal brain contains between 10,000 and 15,000, appear to be completely absent from the brains of narcoleptic patients. If a drug can be synthesized which replaces hypocretin, or at least duplicates its action in the brain, a more permanent treatment, or even a cure, for narcolepsy may become possible.
- Scammell, Thomas E. “The Neurobiology, Diagnosis, and Treatment of Narcolepsy.” Annals of Neurology, 53(2) (2003): 154–166.