Insomnia is a "sleep disorder" that causes difficulties or complete inability to fall asleep, stay asleep for lengthy periods of time, or causes you to wake up too early and be unable to fall asleep again. This disorder can be either short-term (acute) or long-term (chronic).
Hypersomnia is a disorder in which you feel drowsy throughout the day. It might happen even after a long period of sleep. Excessive daytime sleepiness is another word for hypersomnia (EDS). This can be of two types primary and secondary
Narcolepsy and Cataplexy;
Narcolepsy is a chronic sleep disorder characterized by daytime tiredness and sleep episodes. People with narcolepsy find it difficult to stay awake for long periods of time in any situation. Narcolepsy can cause a lot of problems in your daily life. Cataplexy (sudden loss of muscle tone) is a narcolepsy symptom that can be triggered by strong emotions.
Nightmare & Night Terror;
Night terrors and nightmares both start in childhood. Nightmares are disturbing, unpleasant, or terrifying dreams. Nightmares, unlike night terrors, usually happen during REM sleep and don't entail muscular or vocal actions. The facts or sentiments of the nightmare are frequently remembered, and some may even become recurring dreams.