Professor Raj Persaud is a consultant psychiatrist at the Maudsley hospital and senior lecturer at the Institute of Psychiatry in London
"Young people often start to misbehave if they feel the goals they have been set by school or parentsare too high. If they feel hopeless about attaining that goal, they won't see the point in working hard for it. They begin to adopt a can't-be-bothered attitude.
"What you have to tackle as a teacher is the belief in themselves, and the mismatch between what they perceive as their ability and the difficulty of the task. Teachers need to assess the task for these pupils and explain that most people at their level, addressing a subject of that difficulty, will make it.
"There is no point in simply praising students and saying they are able; teachers have to put themselves in the pupil's shoes and see the difficulty from his or her standpoint.
"They also have to be able to persuade parents that putting too much pressure on their children will lead to demotivation, especially for girls, who tend to be more conscientious and aware than boys of what their parents want from them."
Raj Persaud will hold an online behaviour clinic at www.tes.co.uk on November 3