After serving for more than 10 years as the advice columnist for British newspaper The Observer, Mariella Frostrup let readers in on a dilemma of her own that she faces every single night.

While responding to a reader, the "agony aunt" mentioned in passing that she suffers from what she calls an "irrational fear" of the dark, she writes, in her latest column for the paper.

When I went public on my fear of the dark, writing "me too" in what may have been one of my least helpful responses to a troubled reader, a deluge of sufferers wrote to admit they were similarly afflicted. The letters weren't just from those sensibly nervous when wandering an empty street after midnight, but full-on phobics like myself left paralysed with fear and virtually unable to sleep alone. Is it some form of mass hysteria or is the dark, as I've always believed, actually scary?

In an effort to find the ever-elusive peaceful slumber, Frostrup decided to try hypnosis, and spilled her guts to -- uh, interviewed -- a psychotherapist for the essay as well. Click over to The Observer to read the details of her experience.

But is, as Frostrup writes "what seems to me a shameful condition for a near-50-year-old" really that irrational? And if her mailbag is any measure, why are so many adults still shackled by it?

In fact, a fear of the dark in adulthood may be more common than even the sleep experts themselves would think. In a small study presented at the SLEEP 2012 conference in Boston, researchers were surprised to find how many adults 'fessed up to fearing things that go bump in the night.

"We were shocked by how many people acknowledged they were afraid of the dark as adults," study author Colleen Carney, Ph.D., an associate professor of psychology at Ryerson Unversity in Toronto, Canada, told HuffPost's Catherine Pearson.

In Carney's study, the 93 participants dubbed themselves either "good sleepers" or "poor sleepers." Nearly half of the poor sleepers reported at least some fear of the dark, while only a quarter of the good sleepers felt the same, suggesting that the fear might have serious consequences, like insomnia.

For many, this fear of the dark begins in childhood as a fear of the unexpected, Thomas Ollendick, professor of psychology and director of the Child Study Center at Virginia Tech, told LiveScience, that something or someone will pop out of the closet or from underneath the bed. Most grow out of these fears as they get older. A severe fear that persists into adulthood may be classified as a phobia, he said, sometimes called nyctophobia, achluophobia, scotophobia or lygophobia.

In many cases, a phobia of the dark that persists into adulthood is tied to a particularly traumatic childhood experience, psychotherapist Phillip Hodson told Frostrup. However, most are treatable with cognitive behavioral therapy, according to Time's Healthland.

In some instances, though, the underlying fear of the dark can be mistaken for a number of other phobias, or even general anxiety. "People don’t necessarily know they have it. An individual may not be able to fall asleep once it's dark and their mind starts to wander. They think, ‘What if someone breaks into my house?’ Instead of realizing these associations may indicate a fear of the dark, they skip a step and assume they have a fear of burglars,” Carney told Healthland.

Or, they'll follow advice generally dispensed to treat insomnia, like leaving the bedroom when they can’t sleep to do something other than stare at the clock until they feel more tired. “A phobia is maintained through avoidance,” Carney told Healthland. “By not facing the phobia, it’s going to stick around.”

For now, Frostrup is practicing acceptance rather than avoidance. She writes:

I've decided to embrace my early-hours sensitivities as a healthy form of catharsis. Why shouldn't my demons have a bit of a dance when no one else is looking? If my subconscious wants to party while my body is resting who am I to complain, just so long as he keeps himself to himself when I'm up and on my feet?

Are you afraid of the dark? How do you handle it? Tell us in the comments.