What is a key feature of narcolepsy?

Narcolepsy is characterized by sudden and uncontrollable episodes of sleep, often occurring during the daytime. These episodes can happen at any time and may last for a few seconds to several minutes, leaving individuals feeling refreshed but unable to stay awake for long periods. This unique symptom is a hallmark of narcolepsy and significantly impacts the daily lives of those affected by it.

The other options describe features that are not specific to narcolepsy. Intense nightmares may occur in other sleep disorders, like REM sleep behavior disorder, but are not a defining feature of narcolepsy. Inability to reach REM sleep is contrary to what is seen in narcolepsy, as individuals with the condition may enter REM sleep more quickly than those without it. Sleepwalking is associated with disorders of arousal typically occurring in non-REM sleep, rather than a characteristic of narcolepsy. Thus, the proper identification of sudden sleep episodes during the day is key to understanding narcolepsy.