Typically the time you spend sleeping is when your body gets to rest and restore. For people with parasomnias, sleep is not so restful. Parasomnias occur in a state that lies between sleep and wakefulness. 

A person with parasomnias may seem to be alert, walking or talking or eating or doing other such activities but without awareness because the brain is only partially awake. Or a person with a different type of parasomnias may experience sleep terrors or sleep paralysis. These are also a result of the brain being slightly more conscious than usual during sleep. 

Although more common in children, parasomnias can occur at any age. Parasomnias are not in and of themselves worrisome; the main danger is when a person with the condition unknowingly causes injury to themselves or to others.   

“Parasomnias can sometimes be more frightening for the observer than for the person having it,” says Lynelle Schneeberg, PsyD, a Yale Medicine sleep specialist at the Sleep Medicine program. “For example, a child having a sleep terror looks very frightened and this can be very difficult for a parent, but the child will have no memory of this event if awakened or in the morning.” 

It’s typical to cycle through five stages of sleep (stages 1-4 and REM sleep) each night, with stages 1-4 reflecting gradually deeper states of sleep. But the fifth stage, REM (rapid eye movement) sleep, is the only stage during which the brain processes information from the day. It’s also when we most commonly have dreams. 

There are two types of parasomnias: REM-related parasomnias and non-REM related parasomnias. As the names imply, REM-related parasomnias happen during a person’s REM sleep, while non-REM related parasomnias occur during stages 1-4, when the person is not dreaming. Patients are more likely to remember REM-related parasomnia activities than non-REM related ones. REM sleep parasomnias are also more likely to generate verbalizations or scenarios in which the person is acting out something in their dreams.  

A slumbering person is unaware of transitioning from one to the next in the five stages of sleep, but these transitional times are when parasomnias are likely to arise. They are often triggered when a person is slightly awakened during the transition, for instance by noise, temperature changes, sleep apnea (when breathing momentarily pauses during sleep), or restless legs.

While it’s unclear why some people are more likely to have parasomnias, some have been linked to psychiatric disorders such as depression, anxiety, and PTSD. Neurological disorders such as Parkinson’s disease can also increase your risk for parasomnias.

Non-REM parasomnias usually occur among individuals aged 5 to 25 years with a family history of similar parasomnias. REM-related parasomnias can affect people of all ages. 

Parasomnias are usually diagnosed by your doctor based on your medical history and the details you provide about your sleep. Your doctor will ask what the parasomnias are like, how often they occur, when they occur, and what behaviors you exhibit. It may also be helpful to the doctor to review a sleep diary and, if you have a partner, his or her experience of what these episodes are like. 

These are the most common types of actions associated with parasomnias:

Non-REM related parasomnias:

• Sleepwalking: Most common in late childhood and adolescence, sleepwalking describes a person who is up and moving around without being consciously aware. Usually their eyes are open. Once awakened, most sleepwalkers have no memories of walking around. Treatment is not usually required unless the sleepwalking is causing injuries. If loved ones are sleepwalking, you can gently lead them back to bed rather than forcefully waking them up. Remove obstacles or dangerous objects from the area and keep windows and doors locked and closed. If the sleepwalker needs treatment, benzodiazepines, particularly clonazepam, have been shown to be effective.
• Sleep Terrors: Sleep terrors are exactly what they sound like—a person might fight or scream and shows physiological signs of being extremely terrified (fast breathing, tense muscles, and so on). Though their cause is unknown, sleep terrors are more common among people with psychiatric disorders such as depression, anxiety, and obsessive-compulsive and phobic traits. Tricyclic antidepressants and benzodiazepines may be helpful.
• Sleep Talking: Sleep talking is when the sleeper mutters isolated speech or full conversations but has no memory of doing so. It occurs in all sleep states and can be associated with other disorders that cause a person to awaken slightly, REM-related parasomnias and sleep apnea.
• Sleep-related eating disorder: People with sleep-related eating disorders show symptoms of binge eating disorder while half-asleep. A person with this condition may ingest bizarre, even dangerous, things, such as cigarettes they have buttered while semi-conscious. Treatment for sleep-related eating disorders requires the attention of a specialist. One treatment approach is to try to reduce the risk of eating-disordered behavior by following a consistent meal schedule in the daytime. It’s also helpful to avoid alcohol and substance use and follow a healthy sleep routine. If medication is required, the most preferred choice is topiramate. Second-line options are SSRI agents and dopamine agonists.

 REM-related parasomnias

• Sleep paralysis: People with sleep paralysis are unable to move or open their eyes and this happens just as they are falling asleep or waking up. Things that might increase your risk for REM-related parasomnias include not getting enough sleep, irregular sleep-wake schedules, and stress.
• Nightmare disorder: This describes recurrent, intense nightmares accompanied by emotions such as anxiety, anger, or disgust. These nightmares are different from sleep terrors because the patient is able to recall their dreams with great detail and has difficulty going back to sleep. Nightmares are common with acute stress disorder and post-traumatic stress disorder (PTSD), and occur in both non-REM and REM sleep. The nightmares may persist even after other PTSD symptoms have been resolved. This disorder may be treated either with therapy, medication or a combination of both, depending on the severity of the disorder. 

At Yale Medicine we have sleep specialists who are trained to treat a broad range of sleep disorders at the Sleep Medicine program. They use a state-of-the-art lab testing system to pinpoint sleep problems.

For patients with parasomnias, specialists at the Yale program for Sleep Medicine will start by evaluating the sleep environment for triggers, making sure that the sleep environment is very safe, using “scheduled awakenings” for night terrors in a child if these occur at very regular times each night, and the use of medications, if necessary. They will also run tests to rule out any medical sleep disorders that may be triggering these events.