What is one of the primary characteristics of narcolepsy?

Narcolepsy is characterized primarily by excessive daytime sleepiness, which is often manifested as an inability to stay awake during the day. This condition is a neurological disorder that affects the brain's ability to regulate sleep-wake cycles. Individuals with narcolepsy may experience sudden and uncontrollable episodes of sleep, even during activities that require attention. This excessive sleepiness can result in difficulties in staying awake for prolonged periods, leading to challenges in daily functioning.

While frequent nightmares, difficulty in falling asleep, and sleepwalking may be associated with other sleep disorders, they do not define narcolepsy. Frequent nightmares can be more closely related to REM sleep disturbances or other sleep disorders such as nightmare disorder, difficulty in falling asleep is often seen in insomnia, and sleepwalking is typically associated with non-REM sleep disorders. Thus, the inability to stay awake during the day stands out as a key feature of narcolepsy.