If you've ever woken up and not known where you were, how you got there, or who the person lying next to you is — and you hadn't gone out drinking the night before — then you might have had a bout of sleep drunkenness. A new study found that sleep drunkenness affects one in seven people, which is significantly more than researchers had estimated. While the state of confusion can be as harmless as sticking your alarm clock in the fridge, regular instances of the disorder can be dangerous.
Scientists at the Stanford University School of Medicine in Palo Alto interviewed a group of 19,136 American adults about their sleep habits for the study. The researchers asked the participants if they'd ever experienced any symptoms of the disorder; whether they had any mental illness history; and if they were taking any medications. They found that 15 percent of the study group had experienced symptoms in the last year, with more than 50 percent reporting more than one episode per week.
"I was very surprised," Dr. Maurice Ohayon, a professor of psychiatry and behavioral sciences and the study's lead author, told Today. "We had thought that it was not so frequent."
While the name may conjure images of goofy, loopy behavior worthy of a bar story, the disorder isn't exactly a laughing matter.
What Is Sleep Drunkenness?
Sleep drunkenness, known scientifically as confusional arousals, usually occurs during the first part of the night or in the morning after a forced awakening. The disorder causes a state of confusion during which the victim feels disoriented and exhibits inappropriate behavior — you probably felt it that time your alarm started blaring at 4 a.m.
Similar to sleepwalking, the person is not aware of their actions and can experience amnesia of the episode once they're out of the confused state.
What Dangers Does It Pose?
Because you're disoriented and sometimes even unable to recognize your own home or partner, you may exhibit violent or aggressive behavior during sleep drunkenness. The scientists connected the disorder to wild animals' protective instinct upon waking up, which may also help to explain the aggressive behavior.
In the study, the authors wrote:
This mechanism has a protective role for the survival of the animal, which needs to respond quickly to potential threats when it is suddenly aroused. A similar protective mechanism probably exists in humans.
How Is It Related to Mental Illness?
Of the 15 percent of the study group who had exhibited symptoms of sleep drunkenness, 84 percent had another sleep disorder, a mental disorder, or were taking psychotropic drugs such as antidepressants. The leading factor was having another sleep disorder — 70.8 percent of the people who had suffered from sleep drunkenness also suffered from something like sleep apnea, circadian rhythm sleep disorders, or long sleep durations (more than nine hours).
The second-largest link was mental illness, with 37.4 percent of the confusional arousal patients having been diagnosed with conditions such as depression, anxiety, alcoholism, or post-traumatic stress disorder. Individuals who suffered from bipolar disorder or panic disorder were the most likely to suffer from sleep drunkenness.
In a statement, Ohayon said:
These episodes of confused awakening have not gotten much attention, but given that they occur at a high rate in the general population, more research should be done on when they occur and whether they can be treated. People with sleep disorders or mental health issues should also be aware that they may be at greater risk of these episodes.