Over 80 sleep disorders have been identified. Each one changes the quality, length, or time of sleep in its own way. There are five main types of sleep disorders: insomnia (not being able to fall or stay asleep), sleep apnea (breathing stopping during sleep), hypersomnolence disorders (being too sleepy during the day), circadian rhythm sleep-wake disorders (messed up sleep-wake cycles... https://www.medzsquare.com/au/modalert-200