Sleep apnea is a condition in which breathing stops for a period of time, ranging from a few seconds to a couple of minutes. When it becomes severe it can lead to a heart attack or stroke.
Hypersomnia is an excessive need for sleep, either continuous or intermittent, usually more than 12 hours a night.
Narcolepsy, a form of hypersomnia, refers to uncontrollable attacks of daytime sleep, often resulting in hallucinations, muscle weakness or body collapse.
Insomnia can manifest itself as difficulty falling asleep, frequent waking during the night, or an inability to fall asleep again after waking.
Night terrors cause an individual to wake suddenly, sit up, open his/her eyes, scream, moan or cry. Night terrors can last as long as a half hour, after which a person returns to sleep. Unlike nightmares, which are often remembered the next morning, night terrors usually are not.