Why does my friend talk and laugh in sleep?

Q: One of my friends talks and laughs while sleeping. Sometimes, he hits the bed with his hands and legs. What is the cause and treatment for this?

A:These are called parasomnias - sleep talking is a very common parasomnia occurring more commonly in kids. In addition, it is possible that he might have other parasomnias (e.g., REM behaviour disorder) as well if he moves his extremities a lot. Some of the parasomnias can lead to an injury to the individual or the bed partner depending on the severity. Please consider evaluation by a physician specialising in sleep disorders if there is any history of injury to him or his bed partner. Also, take adequate precautions, such as bed padding, making sure sharp objects / weapons are inaccessible to the individual during these episodes; make sure doors and windows are locked, etc.