Examining Mu Opioid Mechanisms of Ketamine’s Rapid Effects in OCD (MKET2) (MKET2)

Randomized, quadruple-blind, parallel mechanistic trial comparing IV ketamine (0.5 mg/kg single infusion) with oral naltrexone 50 mg versus oral placebo in adults with OCD; fMRI acquired before, during, and after infusion.

Primary aim is to probe the role of ketamine's opioid properties in modulating fronto-striatal circuitry and reducing OCD symptoms; a healthy volunteer cohort undergoes one fMRI visit for comparison.