Sleepwalking May Be More Common Than You Think May 14, 2012 -- Do you remember exactly where you were last night? If you are a sleepwalker, maybe not.

Sleepwalking may be more common than experts have estimated, says a California psychiatrist.

"The numbers are very big," says researcher Maurice Ohayon, MD, PhD, DSc, professor of psychiatry and behavioral sciences and director of the Stanford University Sleep Epidemiology Research Center.

In his poll of nearly 16,000 adults, he found nearly 30% reported a history of sleepwalking. That included episodes in childhood and adolescence.

In the previous year, 3.6% said they had sleepwalked at least once. That is estimated to be about 8.5 million adults.

Studies on the number of sleepwalkers are sparse, Ohayon tells WebMD. In one of the few studies done in adults and published 30 years ago, past researchers found 2.5% sleepwalked. Those more likely to sleepwalk were on certain medicines, including some antidepressants, Ohayon found in his current study. They were more likely to have certain disorders, including obsessive-compulsive disorder, he says.

The study is published in the journal Neurology.

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