Confused when you wake up in the morning? Experts say you may have a sleep disorder called "sleep drunkenness."
A new study from the Stanford School of Medicine that tested nearly 20,000 adults suggested the condition could affect as many as 1 in 7 people.
Sleep experts said the symptoms can range from benign ones, like answering the phone instead of turning off your alarm when you wake up, to violent or inappropriate behavior when waking up.
The study, which was published in medical journal Neurology, says 84 percent of cases occurred in people who have other sleep disorders or who are taking antidepressants.
The disorder was more common in people with depression, bipolar disorder, alcoholism or anxiety.
