Scientists have long been aware of a sleep disorder known as confusional arousal, a condition that causes sleepers to awaken feeling disoriented, confused, and uncertain as to where they are. Also known as “sleep drunkenness”, it had been thought that the incidence of these episodes were relatively rare, but new research has revealed that it is happening to more people than sleep scientists had realized, and may be impacted as many as one out of every fifteen adults in the United States. In a report published in the most recent issue of the journal Neurology, researchers from Stanford University School of Medicine interviewed over 19,000 adults ages 18 and older, asking about them a variety of questions about their sleep habits and routines, their medical history and what medications they had taken. Included in their questions were inquiries about episodes of confusional arousal, as well as whether their health history included any mental illness diagnoses. According to lead researcher Dr. Maurice Ohayon, sleep drunkenness is an issue that needs to be better understood, as it can lead to serious injury to the patient or those around them. “There was a case of a man on a ship who awoke in a confused state and fell off the deck to his death,” he said. He adds that others have woken up in such distress and confusion that they have lashed out at the person sharing their bed. The patients rarely remember the incident when asked about it later. He goes on to explain that many people have experienced some version of sleep drunkenness. “This happens to most people occasionally, like when you are jet-lagged.” Those of us who can remember these episodes are different from patients with true confusional arousal in that our episodes are rare, while these are frequent. Ohayon said that in most cases, confusional arousal is accompanied by other sleep problems that the patient may have, which may include obstructional sleep apnea, narcolepsy, or other disorders that may be robbing them of the quality sleep and rest that they need. Treating these conditions generally eliminates the sleep drunkenness as well, though researchers are not yet certain as to whether the other sleep disorders cause the confusion or whether they are separate disorders. According to professor of neurology Dr. David Rye, of Emory University in Atlanta, “Confusional arousals exist – and are probably more common than we thought As in most epidemiological surveys, what is reported are associations, not causes and effects.” The Stanford study showed that of the 19,000 subjects interviewed, 15 percent had experienced confusional arousal at some point during the previous year, with over half of them saying that they had them at a frequency of once per week or more. Of those, 84 percent also reported some kind of sleep disorder, a mental health disorder or the use of antidepressants. Fewer than one percent had no associated problems.