Given the range of variables applicable during the adolescent phase, compliance with treatment is a relatively unpredictable phenomenon. Concordance is important for adolescents with attention deficit hyperactivity disorder (ADHD), as this phase of development encompasses increased areas of responsibility, including: academic standards for future career selection, the development of intimate relationships, exposure to substances of abuse, continued self-concept development and learning to drive. Thus, it is crucial to be able to deal with these issues with sustained concentration, effort, organisation and a good degree of impulse control, all of which can be impaired if the adolescent with ADHD is not on effective treatment. There are a number of general factors influencing concordance as well as some ADHD-specific factors.