KLS is a rare disorder characterised by recurrent bouts of excessive sleep associated with reduced understanding of the world and altered behaviour. KLS usually starts in the teenage years but can occur in younger children and adults. Each episode lasts days, weeks or months during which time all normal daily activities stop. Individuals are not able to care for themselves or attend school and work. People with KLS coming out of episodes will have little or no memory of what happened during an episode. Between episodes they have normal sleep, understanding and behaviour. KLS episodes may continue for 10 years or more. KLS is sometimes referred to in the media as "Sleeping Beauty" syndrome.