Attention deficit hyperactivity disorder (ADHD) is the most common neurobehavioral condition of childhood, with symptoms consisting of inattentiveness, impulsivity and hyperactivity. The diagnosis relies on subjective criteria since there is no objective test for ADHD. Stimulants are the recommended treatment, during the last 2 decades both the rate of its use has increased, and the age for starting treatment has decreased. Adverse side effects have been few, none of which were serious.

Recently, regulators of the Food and Drug Administration (FDA) have been told on forty deaths among patients who took stimulants through 2003. Accordingly, a subcommittee of the FDA recommended that prescription drugs to treat ADHD should be accompanied by strong 'black-box' warnings that they may increase the risk of heart problems in some patients.

To date, there does not appear to have been any study that has evaluated cardiac functions in these patients. In this study we will evaluate the possible long term effect of methylphenidate on cardiac functions, as to provide more knowledgeable basis for decisions on the treatment of ADHD patients with methylphenidate.

Children age 8-18 years who were treated on methylphenidate for more then five years will be allocated in outpatient clinics. Complete EKG and echocardiographic examinations will be performed and cardiac functions, left ventricular mass and left ventricular muscle width will be compared to the normal range of values. The results will give us, for the first time, a basis to support or reject the causative relationship between these drugs and severe cardiac problems.