Two siblings per family participate, one with and one without ADHD. The child without ADHD will attend seven training sessions, and the child with ADHD four. All training sessions are held at home. During the training sessions, the children will learn the correct way to display social behaviour on the basis of example films of desired and undesired behaviour. They will then practice the learned skill through play, first with the therapist and then with their sibling. The child without ADHD will also learn how to playfully teach this behaviour to his/her brother/sister with ADHD and praise him/her.
At the end of the study, it will be examined whether the child with ADHD shows more socially desirable behaviour and less negative behaviour. The children will receive a small reward at the end of the examination.