In this study we try to identify the signature of brain activity in the EEG of attention deficit disorder (ADHD) patients compared to healthy subjects under different doses of Ritalin (methylphenidate) treatment.

In this study we try to identify the signature of brain activity in the EEG of attention deficit disorder (ADHD) patients compared to healthy subjects under different doses of Ritalin (methylphenidate) treatment. All subjects will undergo 1-4 EEG sessions. In each session we will use a different dose of Ritalin or placebo. A detailed neuropsychological tests will be done during the EEG recording. A powerful machine-learning techniques will be used in order to find a specific signature of ADHD and Ritalin treatment in the EEG recording.

Inclusion Criteria:

• Healthy subjects, aged 18-50 years.
• Subjects aged 18-50 years diagnosed with ADHD and treated with Ritalin regularly (at least once a week).

Exclusion Criteria:

• Patients previously diagnosed as suffering from a brain disease except for ADHD.
• Patients after traumatic head injury.
• Patients who are unable to express their consent to participate in the study.