Comparing Oral and IV Methylphenidate Effects

We tested twenty healthy adults who underwent 90-min long PET scans collected in 3 randomly ordered sessions (placebo, oral-MP, and IV-MP; double-blind) while simultaneously recording their self-reported ‘high’ ratings (0–10) under resting conditions, using oral- and IV-MP as pharmacological challenges. In each session, each of the 20 participants was given an oral pill (60mg-MP or placebo) 30 min before injection of the PET tracer ([¹¹C]raclopride), followed 30 min after the tracer by an IV administration (0.25 mg/kg-MP or placebo). Note that these IV- and oral-MP doses were selected because they led to roughly equivalent levels of DA transporter occupancy^{6 (link)}, and their administration times were chosen to ensure that peak concentrations of MP in the striatum had similar timing for oral-MP and IV-MP, relative to imaging initiation^{7 (link)}.