Objective: 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.
Method: 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).
Results: 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.
Conclusion: 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.
Keywords: Attention deficit-hyperactivity disorder, methylphenidate,
preschool children, risperidone