“Findings
The systematic review identified 687 articles, of which 49 RCTs were eligible for analysis, comprising 3299 participants. Standardised mean differences (95% confidence intervals) immediately following the first/single treatment were moderate-high for all conditions (Rac-High: −0.73, −0.91 to −0.56; Esket-High: −0.48, −0.75 to −0.20; Rac-Low: −0.33, −0.54 to −0.12; Esket-Low: −0.55, −0.87 to −0.24). Ongoing effects during repeated dosing were significantly greater than the control for Rac-High (−0.61; −1.02 to −0.20) and Rac-Low (−0.55, −1.09 to −0.00), but not Esket-Low (−0.15, −0.49 to 0.19) or Esket-High (−0.22, −0.54 to 0.10). At follow-up effects remained significant for racemic ketamine (−0.65; −1.23 to −0.07) but not esketamine (−0.33; −0.96 to 0.31). All-cause dropout was similar between experiment and control conditions for both formulations combined (Odds Ratio = 1.18, 0.85–1.64). Overall heterogeneity varied from 5.7% to 87.6%”