Parasomnias are disruptive sleep disorders that cause arousals and abnormal behavior while sleeping.  Diagnostic categories of parasomnias include:

• Non-Rapid Eye Movement Sleep Arousal Disorders
  This type of sleep disorder involves recurrent episodes of incomplete awakening from sleep, usually occurring during the first third of a major sleep episode, accompanied by either one of the following:
  • Sleepwalking – Repeated episodes of rising from bed during sleep and walking about with a blank, staring face, unresponsive to others.
  • Sleep terrors – Recurrent episodes of abrupt terror arousals from sleep, usually beginning with a panicky scream.

During either of these types of sleep disorders, the person has no recollection of what happened and recalls little or no dream imagery. A diagnosis is based on the episodes causing significant distress or impairment in social, occupational, or other important areas of functioning. The disturbance is not attributable to the physiological effects of a substance (e.g., drug of abuse or medication) or to a coexisting mental or medical disorder.

• Nightmare Disorder
  With this sleep disorder, a person has repeated nightmares that usually involve efforts to avoid threats to survival, security, or physical safety. Generally, the nightmare occurs during the second half of a major sleep episode. Upon awakening from the nightmare, the individual rapidly becomes oriented and alert. The sleep disturbance causes significant distress or impairment in social, occupational, or other important areas of functioning, and is not attributable to the physiological effects of a substance (e.g., drug of abuse or medication).
  
• Rapid Eye Movement Sleep Behavior Disorder
  This sleep disorder involves repeated episodes of arousal during sleep associated with vocalization and/or physical movements. The behaviors occur during rapid eye movement (REM) sleep and therefore usually occur more than 90 minutes after going to sleep. Upon awakening from these episodes, the individual is awake, alert, and not confused or disoriented. The behaviors cause significant distress or impairment in social, occupational, or other important areas of functioning (which may include injury to self or the bed partner). The disturbance is not attributable to the physiological effects of a substance (e.g., drug of abuse or medication) or another medical condition.
  
• Restless Legs Syndrome
  With this condition, a person has the urge to movetheir legs, usually accompanied by discomfort in the legs, characterized by all of the following:
  • The urge to move the legs begins or worsens during periods of rest or inactivity.
  • The urge to move the legs is partially or totally relieved by movement.
  • The urge to move the legs is worse at night than during the day.

A diagnosis of restless legs syndrome is based on the symptoms above occurring at least three times per week over a period of at least 3 months. The symptoms cause significant distress or impairment in social, occupational, educational, academic, behavioral, or other important areas of functioning. The symptoms are not attributable to another mental disorder or medical condition (e.g., arthritis, leg edema, peripheral ischemia, leg cramps), are not better explained by a behavioral condition (e.g., positional discomfort, habitual foot tapping), and are not attributable to the physiological effects of a drug of abuse or medication.

• Substance/Medication-Induced Sleep Disorder
  Thissevere sleep disturbance occurs during or soon after substance intoxication or after withdrawal from or exposure to a medication. The sleep disturbance causes significant distress or impairment in social, occupational, or other important areas of functioning.