In a randomized , double-blind trial , comparing SRIs ( clomipramine and paroxetine ) with placebo in 36 adults with OCD ( characterized for subtypes ) , plasma oxytocin was measured with radioimmunoassay after plasma extraction , at baseline , after 1 week , and after 4 weeks of treatment , and related to baseline severity and clinical response after 12 weeks , as measured by the Yale-Brown Obsessive Compulsive Scale ( Y-BOCS ) .