Efficacy of methylphenidate among preschool children with developmental disabilities and ADHD

Abstract

Objective: This was a double-blind, placebo-controlled, crossover design study of the safety and efficacy of methylphenidate (MPH) in 11 preschool children (aged 4.0-5.11 years) with developmental disabilities and attention-deficit hyperactivity disorder (ADHD).

Method: MPH doses of 0.3 and 0.6 mg/kg per dose and a placebo were given. Drug response was evaluated via teacher-completed behavior checklists and clinic-based observations of activity level, attention, and compliance to adult requests. A side effects checklist was also completed by teachers and parents.

Results: Significant improvement on teacher ratings of hyperactivity and inattention as well as clinic-based observations of activity level and compliance were associated with MPH. Eight of 11 preschool children were medication responders (based on a minimum 40% decrease between placebo and one drug condition on either the teacher-rated Conners Hyperactivity Index or the Hyperactive-Distractible subscale of the Preschool Behavior Questionnaire). Five children exhibited significant adverse drug side effects such as severe social withdrawal, increased crying, and irritability, especially at the higher dose (0.6 mg/kg).

Conclusions: Results suggest that preschool children with developmental disabilities and ADHD respond to MPH at rates similar to those of school-age children with mental retardation and ADHD. However, this population appears to be especially susceptible to adverse drug side effects.