Question: I've heard of spilt personality which has somehing to do with human's brain functioning. Does it exist first of all and if it does, then - why is it caused, can it be cured, is there any dangers?

Jen Todd Jones answered on 13 Mar 2013:

Actually split personality is mostly thought of as a psychiatric disorder, there doesn’t appear to be any cause in the brain but someone suffers from a psychological condition. This absolutely does exist but affects a small number of people in the population.

You may be thinking of split brain disorder, this is where the part of the brain that holds the two halves together (called the corpus callosum) is either damaged in an accident or intentionally cut during brain surgery to cure epilepsy perhaps. These people have difficulty coordinating the two sides of their bodies and have trouble with language!