What condition is characterized by uncontrollable sleep attacks?

The condition characterized by uncontrollable sleep attacks is narcolepsy. Narcolepsy is a neurological disorder that affects the brain's ability to regulate sleep-wake cycles. Individuals with narcolepsy experience overwhelming daytime sleepiness and can suddenly fall asleep at inappropriate times, which can occur multiple times throughout the day. This is often accompanied by episodes of cataplexy, which is a sudden loss of muscle tone triggered by strong emotions, but cataplexy itself is a separate symptom rather than the defining characteristic of narcolepsy.

Insomnia, on the other hand, refers to difficulty falling or staying asleep and is not characterized by sudden sleep attacks. Cataplexy, while related, is a symptom that occurs within narcolepsy, and parasomnia involves abnormal behaviors during sleep, such as sleepwalking or night terrors, rather than the uncontrollable sleep attacks seen in narcolepsy. Thus, narcolepsy is the most accurate answer for the condition described.