Everyone loves a good viral video of college-age brotastic pranksters messing with a sleeping buddy, only to have the prank victim abruptly and lash out erratically and violently. As it turns out, according to researchers from Stanford University, there’s a name for the formerly sleeping beauty’s behavior: It’s called sleep drunkenness, and it’s more common than anyone previously believed.

“These episodes of waking up confused have received considerably less attention than sleepwalking even though the consequences can be just as serious,” said study author Maurice M. Ohayon, MD, DSc, PhD, with Stanford University School of Medicine in Palo Alto, CA.

Sleep drunkenness describes a set of behavior as a result of being aroused from sleep abruptly and unexpectedly. It can range from mild (and comical), like confusing the sound of an alarm for a ringing telephone, for instance. However, the incoherence can also be dangerous, leading irritable sufferers to injure either themselves or those around them.

As a caveat, the study had a significant sample size (19,136 people aged 18 or older), but was conducted via survey format. Overall, 15% of those surveyed about their sleep habits reported an incident in the last year, with 50% of those people reporting more than one episode per week. Interestingly, 84% of those who reported incidents of sleep drunkenness also had an accompanying sleep disorder, mental health disorder or psychotropic drug prescription.

Also of interest – there appears to be a correlation between sleep drunkenness and both too much or too little sleep. 20% of subjects getting less than six hours of sleep reported incidents, along with 15% of those getting nine or more hours of sleep.

“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,” said Ohayon. “People with sleep disorders or mental health issues should also be aware that they may be at greater risk of these episodes.”