DOI: 10.36347/sjams.2018.v06i07.012

Pages: 2669-2673

The present study was planned with the objective to evaluate the correlation between autonomic function tests and disease severity as assessed on Vanderbilt Parent Rating Scale(VPRS) in drug naïve patients of ADHD before and after treatment with methylphenidate. Dysfunction in the prefrontal cortex, limbic system, locus coeruleus-noradrenergic system and other related brain structures involving dopaminergic and noradrenergic dysregulation has been proposed as the primary pathophysiological mechanism of the disease. These structures are also included in the neuro-cardiac complex regulation leading to autonomic dysfunction in these patients. Sympathetic underarousal and parasympathetic dominance have been observed in drug naïve patients of ADHD in various studies. Abnormalities in autonomic functions are associated with increased risk of arrhythmias and cardiac mortality. Methylphenidate affects the autonomic functions due to its adrenergic effects. The autonomic functions also get modulated as the disease condition improves. Autonomic function tests (E: I ratio, 30:15 ratio, Cold pressor test, Handgrip test) were performed, and VPRS combined score was assessed on 52 patients of ADHD before and after 12 weeks of methylphenidate treatment. A significant Negative correlation between the E: I ratio(Deep breathing test) and systolic blood pressure change in CPT(Cold pressor test) with Vanderbilt combined score after 12 weeks of methylphenidate treatment was observed. Sympathovagal balance shifts towards the sympathetic arm independent of the adrenergic action of methylphenidate.