Effects of Methylphenidate on Cellular Abnormalities in Children With Attention Deficit Hyperactivity Disorder (ADHD)

An Open-label, Behavioral-treatment-controlled Evaluation of the Effects of Extended Release Methylphenidate on the Frequency of Cytogenetic Abnormalities in Children 6 - 12 Years of Age With Attention Deficit Hyperactivity Disorder (ADHD)

This study will assess the frequency of chromosomal abnormalities measured in circulating lymphocytes in treatment-naive children with Attention Deficit Hyperactivity Disorder (ADHD) treated for 3 months with either extended release methylphenidate or behavioral therapy.

This study will determine whether the administration of extended-release methylphenidate in treatment-naïve children with Attention Deficit Hyperactivity Disorder (ADHD) affects the frequency of chromosomal abnormalities.

Inclusion Criteria:

• Children of both genders, 6-12 years old
• Written informed consent by the parent and the patient (over 7)
• Diagnosis of ADHD
• Age-appropriate cognitive functioning
• All patients who had at least one post-baseline cytogenetic assessment in the core study can enter the observation phase.

Exclusion Criteria:

• History of malignant neoplasm
• History of seizures (except childhood febrile seizures)
• Hyperthyroidism
• Concurrent medical condition which may interfere with study

Other protocol-defined inclusion/exclusion criteria may apply