By Cathy Li

Sleep, an essential everyday routine, is often overlooked. Good sleep is necessary for optimal health and can affect hormone levels, mood, and weight. Some of the most common sleep disorders include insomnia, sleep apnea, narcolepsy, Restless Legs Syndrome (RLS), and REM sleep behavior disorder. In fact, these sleep disorders affect 50 to 70 million U.S adults, and, in particular, insomnia is the most commonly reported. 

Some of the common terms associated with sleeping problems, such as sleepwalking, sleep terrors, sleeptalking, and sleep paralysis, are some of the behavioural manifestations associated with parasomnias. Parasomnias are sleep disorders that occur as physical events or experiences during sleep, and can occur in association with sleep, specific stages of sleep, or sleep-wake transitions. These parasomnias can be disruptive to the patient. 

REM parasomnias include nightmares, which are vivid dreams during sleep that can cause feelings of fear, terror, and anxiety. Usually, the person having a nightmare is abruptly awakened from REM and is able to describe detailed dream content. Nightmares occur frequently in the second half of the sleep period, and the person has difficulty returning to sleep. Nightmares can be caused by many factors, including illness, anxiety, traumatic events, or negative reactions to a medication. 

Sleep paralysis is another REM parasomnia, where individuals are not able to move their body while falling asleep or waking because their muscles are briefly paralyzed. These episodes cause much fear and anxiety during the length of seconds to a few minutes. Sometimes sleep paralysis runs in families, but the cause of sleep paralysis is unknown. Sleep deprivation and irregular sleeping schedules can also cause sleep paralysis. It is also seen in narcolepsy, a disorder that is recognized by its severe excessive daytime sleepiness. Oftentimes, sleep paralysis can often be terminated by sound or touch.

Non-REM parasomnias include night terrors: the person experiencing a night terror abruptly wakes from sleep in a terrified state, accompanied by crying or screaming, as well as an increase in heart rate, breathing, sweating, or flushing of the skin. The person may appear to be awake, but is confused and unable to communicate normally. Night terrors are usually brief, but cases have been known to last up to 30-40 minutes. People who have sleep terrors can often not remember the event the next morning.

Another very commonly observed sleep disorder is sleepwalking, which happens when a person appears to be awake and moving around with their eyes open but is actually asleep. Sleepwalkers usually have no memory of their actions and might wake up in the middle of the episode and appear confused or get back in bed and go back to sleep without waking.

Sleepwalking most often occurs during deep non-REM sleep, early in the night. This sleep disorder is most commonly seen in children aged 6 to 12. However, sleepwalking can occur among younger children, adults, and the elder people. Sleepwalking appears to run in families and can sometimes be dangerous due to the fact that the sleepwalker is unaware of his or her surroundings and can bump into objects or fall down.

Featured image credit: Flickr user RelaxingMusic.