Measuring methylphenidate response in attention-deficit/hyperactvity disorder: how are laboratory classroom-based measures related to parent ratings?

Background: Methylphenidate (MPH) is an efficacious and normally well-tolerated treatment for attention-deficit/hyperactivity disorder (ADHD). Although treatment effects are usually assessed using parent-rating scales, these can be supplemented by more objective methods. Here we examine the associations between ratings and one such method, assessments made across the day in the laboratory classroom.

Method: Comparison of Methylphenidates in the Analog Classroom Setting (COMACS) was made in a large (n = 184) placebo-controlled trial comparing Equasym XL (R)/MetadateCD (R), Concerta (R), and placebo (PLA) using a Laboratory School protocol. Therapeutic effects were measured using direct observation, scores on a simple math productivity task and parent ratings.

Results: Treatment effects were observed on all measures. Laboratory measures were correlated with each other, most strongly between Swanson, Kotkin, Agler, M-Flynn and Pelham Scale (SKAMP) inattention and Permanent Product Measure of Performance (PERMP). Parental ratings were correlated with classroom measures during the main morning period (1.5-4.5 hours after dosing) and to a lesser extent in the afternoon (6.0-7.5 hours after dosing), but not, by and large, immediately after dosing or in the evening. The morning correlations seemed stronger for female than for male participants.

Discussion: The results suggest that parental ratings and direct observations tap different aspects of MPH response and that both may be required for comprehensive assessment.