Sleep Disorders

Common Characteristics

Primary Sleep disorders are divided into two subcategories:  Dyssomnias are those disorders relating to the amount, quality, and timing of sleep.  Parasomnias relate to abnormal behavior or physiological events that occur during the process of sleep or sleep-wake transitions.  We use the term primary to differentiate these sleep disorders from other sleep disorders that are caused by outside factors, such as another mental disorder, medical disorder, or substance use.