This study is an open-label, 6 month trial, of immediate release methylphenidate (MPH-IR) for children with ADHD aimed at assessing whether the observable behavioral changes seen during treatment are associated with potentially more stable underlying modifications in brain functioning (resting-state functional connectivity). Additionally, we will also be looking at treatment effects on neuropsychological processes and reading skills. This information will contribute to the first Brazilian study assessing the cost-effectiveness of the treatment of ADHD. Children with ADHD will be compared to a sample of sex and age-matched sample of typically developing children.

Inclusion Criteria:

The study will include 20 boys aged 8 to 10 years old, regularly enrolled in local schools and directed to the research through advertisement in the media, contact with schools or directly referred to the Attention Deficit/Hyperactivity Program (ProDAH/HCPA) by primary care services for assessment and treatment. Only children with a primary diagnosis of ADHD or with the comorbidity ADHD + reading disorder or ADHD + ODD will be included. Only drug-naïve subjects will be apt to participate in the study.

Exclusion Criteria:

Children who fit into one or more of the following conditions will not be considered eligible to take part in the study: (1) they are outside the age range specified; (2) they are not regularly enrolled and attending school; (3) they have a history of prior or current treatment with psychoactive drugs or psychotherapy; (4) they are mentally retarded (Overall IQ<80); (5) they have a main diagnosis differing from ADHD, including children with other psychiatric or neurological diagnoses