Lack of sleep can really be the root cause of many problems that you might think are not even connected to each other. In my experience with my youngest son, his sleep disterbance (Periodic Limb Movement Syndrome) caused a multitude of problems including never sleeping through the night ( up and down several times), jerking in his sleep constantly, not being able to process information when spoken to directly, tempertantrums, periods of sleep during the day from which he was extremely difficult to wake from ( crashing), what seemed to be learning disabilities, slow growth, hair twirling, destructiveness, carelessness and invisable friends ( whom he blamed for his mistakes, distructiveness, etc). Since being diagnosed by a sleep specialist, he is sleeping 6 hours straight a night, his comprehension levels have drasticly increased, the ADHD types of behaviors have vanished, and his invisable friends have disappeared even to him. The hair twirling has become a sign of him being tired.