AUTHOR=Kaşak Meryem , Günal Okumuş Hande , Çelik Yusuf Selman , Kırşan Fatma Zehra , Öztürk Yusuf , Efe Ayşegül 

TITLE=Novel hematologic ratios and systemic inflammation index in ADHD: effects of methylphenidate treatment

JOURNAL=Frontiers in Psychiatry

VOLUME=Volume 16 - 2025

YEAR=2025

URL=https://www.frontiersin.org/journals/psychiatry/articles/10.3389/fpsyt.2025.1621767

DOI=10.3389/fpsyt.2025.1621767

ISSN=1664-0640

ABSTRACT=BackgroundAttention-deficit/hyperactivity disorder (ADHD) is a common neurodevelopmental disorder, and recent research suggests systemic inflammation contributes to its pathophysiology. This study aimed to evaluate novel inflammatory markers—neutrophil-to-HDL ratio (NHR), lymphocyte-to-HDL ratio (LHR), monocyte-to-HDL ratio (MHR), platelet-to-HDL ratio (PHR), and systemic immune-inflammation index (SII)—in children with ADHD compared to healthy controls. Additionally, it assessed changes in these markers after 12 weeks of long-acting methylphenidate treatment and potential differences among ADHD subtypes.MethodsThis prospective study included 114 newly diagnosed, treatment-naive ADHD patients (aged 6–12) and 52 matched controls. Blood samples were obtained at baseline and after 12 weeks of treatment. Inflammatory markers were calculated from complete blood count and HDL levels. ADHD symptom severity was assessed using the Conners Parent Rating Scale-Revised: Short Form (CPRS-R:S), and anxiety and depression were measured with the Revised Child Anxiety and Depression Scale (RCADS).ResultsADHD patients showed significantly elevated baseline levels of NHR, LHR, MHR, PHR, and SII compared to controls (Cohen’s d range = 0.17–0.69). NHR independently predicted ADHD. Post-treatment, all inflammatory markers significantly decreased, suggesting a potential anti-inflammatory effect of methylphenidate (Cohen’s d range = 0.17–0.91). Post-treatment LHR was higher in the combined ADHD subtype.ConclusionsThis study underscores inflammation’s role in ADHD and suggests these markers may reflect systemic inflammation in ADHD, but their clinical utility requires further investigation.