We think of fear of the dark as something kids have, but now experts speculate that it may be causing insomnia in adults. A Canadian study found that chronic insomniacs show more signs of fear in darkness than people who sleep well. In addition, people who report leaving a light or the television on at night are more prone to sleeping difficulties.
Fifteen percent of adults—primarily older adults and women—report chronic insomnia, meaning they have trouble falling or staying asleep, not getting sufficiently restful sleep, or waking up early.
Insomnia can occur as a side effect of stimulant drugs, unsurprisingly, but also of some allergy medications and antidepressants. Interestingly (or unfortunately), depression can also cause primary insomnia.
If you’re an insomniac, you’ll be tired and irritable. Insomniacs are often sleepy during the day and have trouble with memory and concentration. Doctors typically diagnose insomnia with sleep studies, sometimes asking patients to track their sleeping and waking times, and tiredness.
In the study, researchers surveyed people, including a standard insomnia inventory, and asked them about fear of the dark. Half the people surveyed who were classified as poor sleepers self-reported a fear of the dark, compared to only one in four of the people determined to be good sleepers.
The participants were then startled with random bursts of white noise, first in lit and then in darkened rooms. The researchers measured fear and startle reactions, such as eye blink speed.
What they found was that people who were poor sleepers, including those who didn’t say they experienced darkness phobia, exhibited more fear and were tenser in the dark room than their good-sleeping counterparts. Good sleepers, the scientists found, got used to the noise and were less fearful.
Some specialists have speculated that one way to treat chronic insomnia could be to address the fear of the dark directly. A psychologist could treat the condition using a structured approach to train the patient out of the phobia.