People with narcolepsy tend to

Narcolepsy is a chronic sleep disorder characterized by overwhelming daytime drowsiness and sudden attacks of sleep. People with narcolepsy often find it difficult to stay awake for long periods of time, regardless of the circumstances. Narcolepsy can cause serious disruptions in your daily routine.

Fall asleep when not seeking sleep due to a neurological disorder that decreases the brains ability to control the sleep-wake cycle.

Explanation:

Fall asleep when not seeking sleep due to a neurological disorder that decreases the brains ability to control the sleep-wake cycle.