When people sleepwalk they usually have their eyes open, but typically have a blank look on their face. The sleepwalker will not really see you even if he or she appears to be looking at you. Mostly they just sit or stand up and it only lasts for a few minutes, but sometimes people will get out of bed, get dressed and even leave the house and start the car.

Sleepwalkling or somnambulism is most common in young children, but it can happen at any age. The causes are usually stress, anxiety or exhaustion, especially in adults - in children the causes are less clear. Occasionally it can be a symptom of a brain disorder.

If you see someone sleepwalking, it is very important that you don't shout or try to wake them suddenly, as this can cause a bad shock. The best thing is to gently steer the person back to bed.