Vitamin D in OUD: Exploration of Alterations on the Dopamine D2/D3 Receptor System

The research team is investigating Opioid Use Disorder (OUD), a disorder characterized by dysregulated dopaminergic tone, to evaluate the mechanisms of adjunctive treatment with calcitriol. The investigators will recruit 12 subjects with OUD and 12 healthy subjects to participate in a double-blind, randomized study design where subjects will complete up to 2 Positron Emission Tomography (PET) scans using \[11C\]-PHNO. The investigators will compare subjects in differences between their own study days and in differences between healthy control subjects and subjects with OUD.