A sleep disorder, or somnipathy, is a medical disorder of sleep patterns. Some sleep disorders are serious enough to interfere with normal physical, mental and emotional functioning. Polysomnography is a test commonly ordered for some sleep disorders.
Disruptions in sleep can be caused by a variety of issues, from teeth grinding (bruxism) to night terrors. When a person suffers from difficulty in sleeping with no obvious cause, it is referred to as insomnia. In addition, sleep disorders may also cause sufferers to sleep excessively, a condition known as hypersomnia. Management of sleep disturbances that are secondary to mental, medical, or substance abuse disorders should focus on the underlying conditions.
The most common sleep disorders include:
- Primary insomnia: Chronic difficulty in falling asleep and/or maintaining sleep when no other cause is found for these symptoms.
- Bruxism: Involuntarily grinding or clenching of the teeth while sleeping.
- Delayed sleep phase syndrome (DSPS): inability to awaken and fall asleep at socially acceptable times but no problem with sleep maintenance, a disorder of circadian rhythms.
- Hypopnea syndrome: Abnormally shallow breathing or slow respiratory rate while sleeping.
- Narcolepsy: Excessive daytime sleepiness (EDS) often culminating in falling asleep spontaneously but unwillingly at inappropriate times.
- Cataplexy: a sudden weakness in the motor muscles that can result in collapse to the floor.
- Night terror: Pavor nocturnus, sleep terror disorder: abrupt awakening from sleep with behavior consistent with fear or terror.
- Parasomnias: Disruptive sleep-related events involving inappropriate actions during sleep; sleep walking and night-terrors are examples.
- Periodic limb movement disorder (PLMD): Sudden involuntary movement of arms and/or legs during sleep, for example kicking the legs.
- Rapid eye movement behavior disorder (RBD): Acting out violent or dramatic dreams while in REM sleep (REM sleep disorder or RSD)
- Restless leg syndrome (RLS): An irresistible urge to move legs. RLS sufferers often also have PLMD.
- Situational circadian rhythm sleep disorders: shift work sleep disorder (SWSD) and jet lag.
- Sleep apnea, and mostly obstructive sleep apnea: Obstruction of the airway during sleep, causing lack of sufficient deep sleep; often accompanied by snoring. Other forms of sleep apnea are less common. The air is blocked from entering into the lungs, causing the individual to unconsciously gasp for air. The individual will pause for an average of ten seconds in order to breathe. This is commonly found in overweight, middle-aged men but is also found in people who have suffered from stroke.
- Sleep paralysis: is characterized by temporary paralysis of the body shortly before or after sleep. Often seen as part of narcolepsy.
- Sleepwalking or somnambulism: Engaging in activities that are normally associated with wakefulness (such as eating or dressing), which may include walking, without the conscious knowledge of the subject.
- Nocturia: A frequent need to get up and go to the bathroom to urinate at night.