Dyssomnia

Dyssomnia refers to the group of sleep disorders characterized by difficulty with regard to the amount, timing, or quality of sleep. Because somnia implies sleep and the prefix dys (or dis) signifies “abnormal” or a “bad,” dyssomnia indicates some kind of failure to sleep or the experience of abnormal sleep. The dyssomnias include primary insomnia (cannot sleep), primary hypersomnia (sleeping too much), breathing-related sleep disorder, sleep apnea, narcolepsy, nocturnal myoclonus (or restless legs syndrome), and circadian rhythm difficulties.