Sleep Paralysis Linked to Stress and Genetics

"Sleep Paralysis" is a disorder in which people may feel like they can't move their body when they're falling asleep or waking up, and often report hallucinations of "a malevolent presence" pressing down on them. A new study suggests the phenomenon may have a genetic cause.

In the study prepared by the University of Sheffield in England and published online Feb. 9 in the Journal of Sleep Research, researchers asked a group of more than 800 twins and siblings whether they had experienced sleep paralysis. The results showed that genetics were partially to blame for the strange phenomenon. In addition, the people in the study who had anxiety, slept poorly or had experienced stress in their lives were more likely to have these nighttime bouts of paralysis, the researchers found. The findings shed some light on what is still quite a mysterious condition.

 Sleep paralysis often occurs during the rapid eye movement (REM) stage of sleep, when people are usually dreaming. In REM sleep the muscles are nearly paralyzed, possibly to prevent people from acting out their dreams. Some people who suffer from sleep paralysis experience hallucinations of a "terrifying figure" pressing down on them and preventing them from moving. Estimates of how many people experience the phenomenon vary widely; some studies report that app. 7 percent of people will experience the feeling at some point in their lives, while other studies suggest that it affects as many as 60 percent. Yet scientists don't really know what causes the phenomenon.

Researchers used data from 862 twins (identical and nonidentical) and other (non-twin) siblings between ages 22 and 32 in England and Wales. The participants indicated on the survey whether they agreed with the statement, "Sometimes, when falling asleep or waking up from sleep, I experience a brief period during which I feel I am unable to move, even though I think I am awake and conscious of my surroundings."

By comparing the responses of identical twins who share almost all of their DNA with those of nonidentical siblings who only share about half of their DNA, the researchers found that genes accounted for more than 50 percent of the incidence of sleep paralysis. They also found that sleep paralysis was more common in people with anxiety, those who weren't getting good sleep and those who had had traumatic experiences, such as an illness or death in the family.

The researchers then studied the participant's PER2 genes, which are linked to the circadian rhythms. They found that the people who had certain versions of this gene were more likely to have sleep paralysis, intimating that something to do with the control of circadian rhythms is probably involved in sleep paralysis.

The study has a number of limitations; it was based on a relatively small number of participants, and was limited to young adults. In addition, the findings don't prove that genetics or stressful factors cause the paralyzing experience, only that the two are linked; Researches still aren't sure whether anxiety could cause a person to experience sleep paralysis, or if experiencing sleep paralysis can make a person more anxious. However their conclusions indicate that sleep paralysis appears to be heritable, and there seem to be some genes influencing sleep and wake patterns involved.

---

References:
 livescience.com

New Studies on Confusional Arousals

Parasomnias are a group of disorders that include behaviors that occur around sleep. Confusional arousals are a common parasomnia affecting children; generally mild episodes in which a person wakes up or arouses from sleep and remains in a confused state, they are characterized by the affected person briefly seeming to wake up, sit up, and even look around. The episodes last from seconds to minutes, and they may not be responsive to stimuli.

But according to a new study published in the journal Neurology, as many as 1 in 7 adults may have this disorder. Popularly referred to as "sleep drunkeness",  the episodes usually happen when a person wakes suddenly, and people may have no memory of these incidents. In the study, the researchers interviewed a random sample of more than 19,000 American adults about their sleep habits and history of confusional arousal, as well as any mental illness and any medications they were taking.

Approximately 15 percent of those surveyed said they had experienced at least one episode in the previous year, more than half claiming that they suffered at least one episode per week. Slightly fewer than 10 percent of those who had had an episode couldn't remember part or all of the experience, and 15 percent of them also had sleepwalking episodes.

Confusional arousal is different from the normal sleepiness that most people feel when they wake up; most people with sleep inertia, the feeling of grogginess most people experience after awakening, will remember the experience. But people suffering from confusional arousal are not aware of their actions, and attempts to fully wake them usually fail.

 The researchers found that among those who'd had a confusional arousal episode, 70 percent also had a sleep disorder and 37 percent had a mental illness. Only 31 percent were taking medication for these disorders, and these were mostly antidepressants. People suffering from depression, bipolar disorder, alcoholism, panic or post-traumatic stress disorder and anxiety seemed more susceptible to the disorder, as did those with sleep apnea.

Confusional arousal can result from getting too little or too much sleep; about 20 percent of people who reported getting less than 6 hours of sleep per night reported having an episode, and 15 percent of those who got at least 9 hours per night said the same, the researchers said.

The prevalence of these parasomnias may be cause for concern, and the disorder could have major consequences if it affects people with responsibility for the safety and security of others, such as pilots or emergency-room doctors. CSMA's sleep centers throughout Greater Houston provide treatment to patients suffering from parasomnias and confusional arousals. For more information visit the HoustonSleep.net or call us today at (281) 407-6222.

---

Reference:
http://www.livescience.com/47539-strange-sleep-disorder-drunkenness.html