Change in vital parameters at first methylphenidate administration as a predictor of treatment response at six-month follow-up.

Methylphenidate is the primary pharmacological treatment for attention-deficit/hyperactivity disorder (ADHD), yet approximately 30% of patients show a poor clinical response. Currently, no reliable biomarkers exist to predict which patients will benefit from treatment. Emerging evidence suggests that methylphenidate-induced increases in blood pressure are associated with improvements in attention and underlying neurobiological mechanisms. Blood pressure could thus serve as a low-cost, accessible predictor of methylphenidate response. The aim of this study was to explore whether acute changes in vital signs-specifically blood pressure and heart rate-after a single methylphenidate dose can predict clinical response after six months of treatment in children and adolescents with ADHD. The final sample consisted of N = 171 children and adolescents (M:F = 148:23; mean age = 9.83 ± 2.61 years, range = 5.27-16.17) diagnosed with ADHD, and ADHD symptoms were assessed using the SNAP-IV. In this context, data on vital parameters and severity of symptoms made during the first single-dose methylphenidate administration and at 6-month methylphenidate monotherapy were retrieved from patients' medical records. Our findings showed that greater increases in blood pressure during the first methylphenidate administration were associated with greater symptom reduction over time (Inattention: β = 0.202, t = 2.452, p = 0.015; Hyperactivity/Impulsivity: β = 0.225, t = 2.743, p = 0.007; Combined: β = 0.233, t = 2.837, p = 0.005). These results suggest that early cardiovascular response may serve as a low-cost, accessible predictor of treatment efficacy, supporting more individualized approaches to ADHD pharmacotherapy.