tokens: RESULTS : Olanzapine - treated patients demonstrated a statistically significant greater mean ( + / - SD ) improvement in Y - MRS total score than placebo - treated patients ( - 14 . 8 + / - 12 . 5 and - 8 . 1 + / - 12 . 7 , respectively ; P < . 001 ) , which was evident at the first postbaseline observation 1 week after randomization and was maintained throughout the study ( last observation carried forward ) .