The purpose of this study is to investigate the association of adverse environmental factors, parental psychopathology, family functioning and genetic factors and the response to methylphenidate treatment in children and adolescents with Attention Deficit/Hyperactivity Disorder.

Attention Deficit/Hyperactivity Disorder (ADHD) is a chronic disorder, with a worldwide estimated prevalence of 5,29%. It is associated with a high risk of functional impairment in many aspects of the patient´s life, such as academic achievements, peers relationships and physical injuries. There are few studies assessing predictive factors of clinical response to treatment. Different patterns of family functioning, such as high family conflict and low family cohesion might be associated with a poor treatment response, possibly mediating the effects of higher severity af the disorder and/or higher prevalence of comorbidity. Parental psychopathology has been associated with a poorer prognosis and is related with family functioning. Adverse social factors have long been studied and are associated with an increased risk for general mental disease, including ADHD, as well as a poorer prognosis. Different genetic factors have been studied and associated with different aspects of the disorder and different clinical responses to treatments. There are no studies evaluating how those factors interact with each other in a Brazilian population.

Inclusion Criteria:

• ADHD
• Age: 5 - 18
• Primary Indication of Methylphenidate

Exclusion Criteria:

• IQ < 70
• Clinical conditions that preclude use of methylphenidate