Ever woken up on a Saturday and started frantically getting ready for work? Or answered your phone thinking the alarm clock was an incoming call? If so, you’re one of 15% of people who have experienced “sleep drunkenness.”

This strange condition, also known as “confusion arousal” is described as a feeling of disorientation upon waking. New studies conducted by the Stanford University School of Medicine found that not only is sleep drunkenness quite common, almost 1 in 10 people actually experience it once a week or more.

In most cases the incidents were fairly harmless – participants recalled waking up in a hotel and having no idea where they were, or being unable to find the bathroom in their own home.

Some of those surveyed, however, revealed that they’d become violent when woke suddenly, punching or hitting their partners. Researchers believe that this is due to the “startle reflex” which is triggered when we are abruptly awoken by an alarm or a noise in the room. Our bodies are put on high alert so that we can protect ourselves if needed – and action comes before reason. Scary!

Common causes of sleep drunkenness are not getting enough sleep – less than 6 hours per night on a regular basis – or indeed getting TOO much sleep – more than 9 hours per night. But if you experience extreme confusion upon waking more than once a week, it could be a sign of a sleep disorder, so do consult a doctor!