Neurocognitive effects of switching from methylphenidate-IR to OROS-methylphenidate in children with ADHD

Objectives: This study evaluated neurocognitive changes after switching from immediate release forms of methylphenidate (MPH-IR) to osmotic release oral system methylphenidate (OROS-MPH). Methods: 102 children with attention-deficit/hyperactivity disorder (ADHD) participated in an open label, 28 day trial, performing neurocognitive test at baseline and at 28 days after the switch from MPH-IR to OROS-MPH. Results: There were significant improvements in the commission error and the reaction time of both visual and auditory continuous performance tests (CPTs) at 28 days after switching from MPH-IR to OROS-MPH. A positive correlation was observed between the improvement in parent/ caregiver-rated IOWA Conners total score (Δ IOWA) and the reduction in commission error (r = 0.3, p = 0.001) and reduction in reaction time variability (r = 0.3, p = 0.006) of visual CPT. In a linear regression model, the change in parent/caregiver-rated IOWA Conners scale total scores were significant predictors of change in commission error (β = 0.3, p = 0.005, CI = 0.4-2.3, adjusted R² = 0. 12) and RT variability (β = 0.3, p = 0.004, CI = 0.5-2.4, adjusted R² = 0. 09) of visual CPT. Conclusions: These data suggest that MPH-IR may be successfully switched to OROS-MPH treatment with associated improvements in neurocognitive performance. Large-scale controlled trials are needed to replicate these findings.