Poor Sleepers, Good Sleepers
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.
Fear of the Dark, Insomnia: Perspectives
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.
Treating Fear of the Dark
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.