Treatment Trajectories of Methylphenidate versus Risperidone in Preschool ADHD: A 12-Week Retrospective Study

The objective of this study was to evaluate and compare the 12-week trajectories of symptom change and functional outcomes associated with methylphenidate and risperidone monotherapies in preschool-aged children with ADHD across four sequential evaluation points.

This naturalistic, non-randomized retrospective chart review, in which treatment allocation was based on routine clinical practice, analyzed clinical data from 38 drug-naïve male preschool children (aged 52–72 months) who completed a 12-week monotherapy regimen (methylphenidate, n=20; risperidone, n=18). Treatment outcomes were assessed at baseline (T0), week 3 (T1), week 6 (T2), and week 12 (T3) using the Conners’ Parent Rating Scale-Revised Short Form (CPRSR: S) and the Strengths and Difficulties Questionnaire (SDQ).

Two-way repeated measures ANOVAs indicated no statistically significant Time × Group interactions for any CPRS-R:S subscales (p >0.05), with both monotherapies showing a parallel, significant reduction in core ADHD symptoms that stabilized after week 6 (T0 > T1 > T2=T3). In contrast, significant Time × Group interactions were observed across multiple SDQ dimensions (p <0.05). In the methylphenidate group, significant reductions in global behavioral difficulties were observed by week 3, whereas the risperidone group showed a more gradual trajectory, with improvement in conduct problems becoming evident after week 6 and improvement in emotional symptoms becoming evident at week 12.

Both methylphenidate and risperidone monotherapies were associated with substantial reductions in core diagnostic ADHD symptoms over 12 weeks in preschool children. However, they demonstrated distinct trajectories across broader functional domains: functional improvement emerged earlier in children receiving methylphenidate, whereas children receiving risperidone showed a more gradual and time-dependent pattern of behavioral improvement.