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. 2020 May 21;3(5):e204693. doi: 10.1001/jamanetworkopen.2020.4693

Figure 2. Standardized Mean Difference (SMD) in Total Symptoms Scores for Healthy Volunteers After Ketamine vs Placebo Administration.

Figure 2.

Scores include Positive and Negative Syndrome Scale and Brief Psychiatric Rating Scale. A statistically significant increase in total symptoms occurred in healthy volunteers in the ketamine condition compared with the placebo condition (SMD = 1.50 [95% CI, 1.23-1.77]; P < .001). Each square shows the effect size for a single study, with the horizontal error bars representing the width of the 95% CI. The size of the squares reflects the weight attributed to each study. The diamond illustrates the summary effect size, and the width of the diamond depicts the width of the overall 95% CI.