Fig. 3. Analysis of change of clustered rating scores for subjective cognitive capacity revealed less decline after R  (−)- (P = 0.040) or S  (+)-ketamine (P = 0.042) than after racemic ketamine for the overall period at 60 min. Bars show the mean ± SD. *Significant difference between racemic ketamine and S  (+)-ketamine. †Significant diffference between racemic ketamine and R  (−)-ketamine.