Perhaps one of the most famous and disturbing sleep-related disorders is narcolepsy — the condition in which a seemingly fully alert person suddenly and without warning becomes drowsy and falls asleep. While the cause of narcolepsy is not completely understood, current research points to a combination of genetic and environmental factors that influence the immune system. Narcolepsy occurs in one in approximately 2,000 people in the United States.
Narcolepsy is a neurological disorder that affects the brain’s ability to control sleep-wake cycles. It involves abnormal onset of REM sleep and REM sleep intrusion into daytime wakefulness. Rather than progressing through a series of sleep stages, persons suffering from narcolepsy involuntarily fall into dream sleep at any time.
The hallmark signs of narcolepsy are excessive daytime sleepiness (including episodes of irresistible sleepiness) combined with sudden muscle weakness. The sudden muscle weakness may be elicited by strong emotion or surprise. Episodes of narcolepsy have been described as “sleep attacks” and may occur in unusual circumstances, such as in the middle of an activity like driving, eating, talking, or walking. Other symptoms may include vivid dream-like images or hallucinations, leg jerks, nightmares, restlessness, and total paralysis just before falling asleep or just after waking up. These symptoms can develop suddenly or over many years. Narcolepsy often takes years to recognize in patients since many medical conditions present with fatigue as a symptom.
To diagnose narcolepsy, a set of sleep studies is performed - an overnight diagnostic polysomnography followed by a multiple sleep latency test the next day. Treatment may include stimulant medications combined with behavioral interventions, such as regularly scheduled naps, to minimize the potential disruptiveness of narcolepsy on the individual’s life.