Dr Byron, educational psychologist for Hampshire local authority, cites one 14-year-old who came to see him. "He was bouncing up and down on the chair, slapping his face at times. But I couldn't believe that this was normal behaviour for the boy."
It transpired that he had trouble sleeping. He would regularly spend hours at a time lying awake in bed. After several hypnosis sessions, Dr Byron gave the boy a tape to help him relax on his own.
At the next session, the boy arrived looking worried. He had been unable to listen to the tape all the way through, he confessed, because he kept falling asleep.
"Lots of things fell into place," says Dr Byron. "Before, he'd been wiped out at school and couldn't concentrate. Once he was sleeping, it was a lot easier for him to get on at school. He started to get more control over his life."
Often, pupils who see Dr Byron do not even mention problems they may have at school.
"I ask them to talk about what's bothering them and we deal with that," he says. "They don't have to publicise everything."
Chris Travell, consultant educational psychologist for Hampshire, agrees.
"You have to look at the whole lives of young people, what's going on inside and outside school," he says.
"Lots of things in their lives can have an impact on behaviour and attendance. Hypnosis gives young people the skills to deal with their anxiety and to create an environment where change can take place."