Controlling for antipsychotic agents , a mixed model showed that patients who received adjunctive bexarotene had significantly lower PANSS positive scale scores compared to patients who received placebo ( F = 8.6 , P = .003 ; treatment arms time , F = 2.7 , P = .049 ) , with moderate effect size ( d = 0.48 ; 95 % CI,0.04-0 .93 ) .