Excessive Sleepiness Plagues Many Americans June 8, 2010 -- About 20% of Americans complain of excessive sleepiness, a new study shows. It's a finding that raises concerns about public safety and the potential for accidents and injuries.

Research at Stanford University finds that not only do 19.5% of U.S. adults report moderate to excessive sleepiness, but 11% report severe sleepiness.

And excessive sleepiness is much more common in the U.S. than in Europe, Stanford sleep scientist Maurice Ohayon, MD, PhD, says in a news release. He reported in a study published in 2002 in the journal Neurology that the prevalence of excessive daytime sleepiness in five European countries was 15%.

Researchers studied data from a representative sample of 8,937 people 18 or older living in Texas, California, and New York. The participants were interviewed by telephone about their sleeping habits, health, sleep problems, and mental disorders.

Excessive sleepiness can be a symptom of other medical problems, including sleep disorders such as obstructive sleep apnea, a breathing problem that occurs when muscles relax during sleep, causing soft tissue in the back of the throat to collapse and block the upper airway.

Shift work disorder involves complaints of insomnia or excessive sleepiness in people who are scheduled to work during their normal sleep hours, often accompanied by reduced alertness and impaired mental ability, which can contribute to accidents.

"Insufficient sleep is plaguing the American population and is one of the leading factors for excessive daytime sleepiness," says Ohayon, a professor of psychiatry at Stanford and director of the Stanford Sleep Epidemiology Research Center in Palo Alto, Calif.

Severe sleepiness was more prevalent in women than in men, 13% to 8.6%, Ohayon says in an abstract presented at SLEEP 2010, the 24th annual meeting of the Associated Professional Sleep Societies.

Feeling Drowsy When You Need to Be Alert

The study also shows:

• 17.7% of participants said they fell asleep or were drowsy in situations that required a high level of concentration, such as in conversations and in meetings.
• 18.2% reported sleepiness in situations requiring low concentration, such as television viewing or reading.
• People with obstructive sleep apnea were three times more likely to be sleepy.
• People with a diagnosis of insomnia and those who said they sleep for six hours or less were more than two and a half times more likely to report drowsiness.
• People who work at night and those with major depressive disorder were almost two times more likely to report sleepiness.