A sleep disorder, or somnipathy, is a medical disorder of a person's sleep pattern and which can interfere with normal physical, mental, social and emotional functioning. Some common sleep disorders include insomnia (chronic inability to sleep), sleep apnea (abnormally low breathing during sleep), narcolepsy (excessive sleepiness at inappropriate times), cataplexy (sudden and transient loss of muscle tone), and sleeping sickness (disruption of sleep cycle due to infection). Treatments for sleep disorders include behavioral and psychotherapeutic treatments, rehabilitation and management, use of medications, and other somatic treatments.