Jun 11, 2012 5:01 AM
June 11, 2012 -- Insomnia in some adults may be driven by a fear of the dark, Canadian researchers say.
In their small study of 93 college men and women, Ryerson University researchers found more poor sleepers than good sleepers confessed a fear of the dark.
"I think the most surprising part of the study is that people told us," says researcher Colleen Carney, PhD, associate professor of psychology at Ryerson University, Toronto.
She and her team confirmed participants were afraid of the dark during sleep lab experiments.
The research is being presented at Sleep 2012, the annual meeting of the Associated Professional Sleep Societies, in Boston.
Insomnia is a common sleep disorder. It affects about 30% of adults within a given year, according to the American Academy of Sleep Medicine. Up to 15% say they have chronic insomnia.
Insomnia can include difficulty falling or staying asleep, waking up too early, or having poor-quality sleep.
It can occur as a side effect of medications such as antidepressants, allergy drugs, or stimulant drugs used for such conditions as ADHD. It is more common with age and among women, according to the National Sleep Foundation.
Carney and her colleagues decided to focus on fear of the dark after she heard many people with insomnia, over the years, talk about sleeping with a light or TV on.
The researchers asked all 93 men and women, average age 22, to complete questionnaires about sleep habits.
One is called the Insomnia Severity Index. It helps classify people as poor or good sleepers.
They then assigned them to a poor-sleeper group or a good-sleeper group. There were 42 poor sleepers and 51 good sleepers.
Of the 42 poor sleepers, almost half said they were afraid of the dark.
Of the 51 good sleepers, just about one-quarter were afraid of the dark.
In the sleep lab, Carney tried to confirm the fear of the dark. She exposed both the good and poor sleepers, four different times, to a burst of white noise.
"If you are nervous, you are going to flinch," Carney tells WebMD.
Researchers observed their responses, such as blinking speed and other measures that evaluate the amount of fear.
"We measured the blinks, the size, and how fast," Carney says. The participants were measured twice in a simulated bedroom setting that was lit and twice in the same setting while dark.
''The poor sleepers tended to blink fast in the dark in response to the unexpected noise," Carney says.
Not so the good sleepers. The poor sleepers had greater ''startle'' responses only in the dark, she found.
The good sleepers tended to get used to the burst of white noise, Carney says.
"That's what you do when you aren't afraid," she says. "The poor sleepers actually became more afraid."
Her conclusion: Fear of the dark may contribute to increased arousal once the lights are turned off for the poor sleepers.
The study makes sense to Karl Doghramji, MD, medical director of the Jefferson Sleep Disorders Center at Thomas Jefferson University in Philadelphia.
"In my experience insomniacs have many fears and concerns, many of which they are not necessarily consciously aware of," he says, until they think more closely. He reviewed the study findings.
"This emphasizes the point that understanding the mind of the insomniac can be very important in determining the cause of the insomnia and formulating its treatment."
The fear of the dark, he says, may be due to other fears, such as a fear of having a bad dream, or the fear of loss of control during sleep.
Maurice M. Ohayon, MD, PhD, DSc, director of the Stanford University Sleep Epidemiology Research Center, agrees. "I think there is a fear to falling asleep, to losing control of themselves, [a fear] that something very bad will happen," he says.
To help the insomnia, Carney says those who have a fear of the dark should work directly on the fear, or phobia.
Doghramji agrees. "I think the most desirable treatment would be psychotherapy," he says. Among the types, talk therapy aimed specifically at changing their behavior.
This would typically involve a structured treatment approach, with a limited number of sessions. The therapist helps patients look at negative thinking and respond to challenging situations in a more effective way.
These findings were presented at a medical conference. They should be considered preliminary as they have not yet undergone the "peer review" process, in which outside experts scrutinize the data prior to publication in a medical journal.