Dose-response effects of chronic methylphenidate administration on late event-related potentials in attention deficit...

Stimulants, such as methylphenidate, are extensively used in the treatment of attention deficit disorder. In the present study, we used a double-blind placebo-controlled, prospective protocol to evaluate the effects of methylphenidate (MP) (dose 0.1 and 0.33 mg/kg three times daily) on the late event-related potentials, some of which are considered biological attention correlates. Sixteen patients, 6-15 years old, were tested, using an auditory target selection paradigm. The latencies of N200 and amplitudes of P150 increased with MP (p less than 0.01). These effects are in the direction of normal maturational change. The latencies of P300 tended to be shorter in adolescents than in children, and with high MP dose the P300 latencies became even shorter in adolescents but were prolonged in children (p less than 0.05). This pattern of change supports the view that pharmacological interactions with various cerebral phenomena including cognition may be age-specific.