Fig. 2: Summary of meta-analysis results.

Odds ratios (OR) and 95% confidence intervals (CIs) comparing MDMA-AP with control groups on all primary outcomes and secondary outcomes that achieved statistical significance (p < 0.05). OR > 1 indicates an increased likelihood of the event when treated with MDMA-AP compared with control groups and an OR < 1 indicates a reduced likelihood. Phase 2 studies: odds of experiencing any side effects during medication sessions was higher in the MDMA-AP group compared to control groups (p = 0.01), with anxiety and jaw-clenching more likely in the MDMA-AP group compared to control groups (ps < 0.05). Odds of experiencing any side effect in the 7 days following medication sessions were also higher in the MDMA-AP group compared to control groups (p = 0.007). Phase 3 studies: odds of experiencing any treatment emergent adverse events was higher in the MDMA-AP group compared to control groups (p < 0.001), with muscle tightness, decreased appetite, nausea, excessive perspiration, feeling cold, restlessness, dilated pupils, jaw clenching/tight jaw, uncontrolled eye movements, feeling jittery, non-cardiac chest pain/discomfort, blurred vision, and chills more likely in the MDMA-AP group compared to control groups (ps < 0.05). There were no other significant associations in Phase 2 or 3 studies.