In the primary intention-to-treat analyses , DCS did not augment the effects of CBT compared with placebo ( mean [ SD ] clinician-rated Y-BOCS score , DCS : 13.86 [ 6.50 ] at week 12 and 12.35 [ 7.75 ] at 3-month follow-up ; placebo : 11.77 [ 5.95 ] at week 12 and 12.37 [ 6.68 ] at 3-month follow-up ) but showed a significant interaction with antidepressants ( clinician-rated Y-BOCS , B = -1.08 ; Z = -2.79 ; P = .005 ) .