The safety and efficacy of methylphenidate (MPH), 0.3 and 0.6 mg/kg, in 11 preschool children (aged 4-5 years) with developmental disabilities and attention deficit hyperactivity disorder (ADHD) were determined in a double-blind, placebo-controlled, crossover study at the Western Psychiatric Institute, University of Pittsburgh, PA. IQs ranged from 40 to 78 (mean, 60). No child had autism/PDD. A positive response to MPH was obtained in 73%. Teacher ratings of hyperactivity and inattention and clinic-based observations of compliance and activity level were significantly improved. Adverse MPH side effects in 5 (45%) patients included severe social withdrawal, crying, and irritability. 
COMMENT. Preschool children with ADHD and developmental disabilities respond to MPH at rates similar to those of school-age children with mental retardation and ADHD, but the risk of adverse drug effects is greater. Social withdrawal and irritability are frequent, especially at higher doses. A combination approach, behavioral intervention and lower MPH dose, might reduce the risk of side effects.
Are stimulants overprescribed? is addressed in a study of the diagnosis and treatment of ADHD in four US urban/suburban communities, including Puerto Rico . Only 12.5% of children with a diagnosis of ADHD had received stimulant medication in the previous 12 months. Mental health counseling and/or school-based interventions were used more often than medication. Stimulants are not overprescribed, and their potential effectiveness may be neglected due to cultural or physician bias or lack of parent education.