Understanding Non-Rapid Eye Movement Sleep Arousal Disorders
Non-rapid eye movement sleep arousal disorders are a pair of conditions listed in the newest edition of the mental health professionals’ guidebook called the Diagnostic and Statistical Manual of Mental Disorders (commonly known as DSM 5). The two disorders—called sleepwalking disorder and sleep terror disorder—are grouped together because they both feature unusually aroused or agitated states of mind that occur during a part of the nightly sleep cycle called non-rapid eye movement sleep. The American Psychiatric Association, creator of DSM 5, views these conditions as mental health concerns because of their potential to degrade the waking psychological function of affected individuals.
Non-rapid eye movement sleep (NREM sleep) is the collective name for four individual, consecutive stages of sleep that all people go through during every extended sleeping session. These stages get their name because they lack the classic involuntary eye movement that occurs during a fifth stage of sleep, called rapid eye movement (REM) sleep. The various NREM stages make up roughly 80 percent of all sleep, the University of Maryland Medical Center reports. The remaining 20 percent, dedicated to REM sleep, occurs in blocks of time that repeat roughly every hour and a half. Much of the rest and restoration gained from sleep, including recuperation from daily cell and tissue damage, comes during the last two non-REM stages. Both of the non-rapid eye movement sleep arousal disorders belong to a larger group of sleep-related conditions called parasomnias. All parasomnias involve some sort of significant disturbance of either non-REM or REM sleep.
People with sleepwalking disorder participate in a number of simple and complicated activities normally associated with a conscious state of mind—including walking, talking, getting dressed, using the bathroom, fixing food, or driving—while still asleep. Some affected individuals develop a subtype of the condition called nocturnal eating disorder or sleep-related eating disorder, which typically involves the consumption of fattening foods that don’t normally play a prominent role in their daily, waking diets. Sleepwalking disorder patients sometimes remember limited aspects of their sleeping behaviors the next day, but never fully recall their actions.
The National Sleep Foundation estimates that roughly 1 percent to 15 percent of Americans sleepwalk. While this behavior appears most often in younger children, it also appears with some frequency in teens and adults. Despite sleepwalking disorder’s status as a mental condition, affected individuals don’t typically have other mental health concerns that act as an underlying source of their sleep-related problems. Instead, things that tend to trigger the condition include any infection or illness that produces a high fever, alcohol use, use of sedative medications, use of specific non-sedative medications, a chronic lack of adequate sleep, and the presence of a sleep-related condition called obstructive sleep apnea.
Sleep Terror Disorder
Sleep terror disorder is also sometimes known as night terror disorder. People with this condition experience highly distressing emotional states that are more or less identical to those found in people who experience nightmares. However, unlike people with nightmares, people with sleep terror disorder stay asleep throughout their experiences instead of waking up. In addition, while individuals affected by nightmares often recall their dreams in great detail, individuals affected by sleep terrors either only vaguely recall their experiences or don’t recall them at all. Specific behaviors that can outwardly mark a bout of sleep terror include unusually heavy breathing, abnormal thrashing or kicking movements, sitting upright while asleep, shouting or making other loud vocalizations, jumping out of bed, attacking a sleeping partner, and failing to wake up when prompted by others.
The Mayo Clinic identifies a number of factors that increase the chances of developing sleep terror disorder. They include chronic lack of sleep, sleeping in a new or strange place, sleeping in an unusually loud or bright environment, the after-effects of unusual daytime tiredness, and the after-effects of daytime anxiety or stress. Children with fevers also have heightened risks for the disorder. Additional potential causes or contributing factors include alcohol use, sedative use, antihistamine use, illicit drug use, obstructive sleep apnea, traumatic blows to the head, and migraine headaches. Roughly 3 percent of U.S. children suffer from sleep terrors; the condition also affects about 1 percent of U.S. adults.
According to guidelines established by the American Psychiatric Association, sleepwalking and sleep terrors only qualify as mental health concerns in certain circumstances. Criteria for making a mental health diagnosis include the presence of repeated episodes of either sleepwalking or sleep terrors, lack of responsiveness during an episode, lack of full awareness of an episode after the fact, and the onset of substantial, waking mental anguish or life disruption in association with sleepwalking or sleep terrors.