Figure 2. Characteristics of included clinical trials. (A) Clinical trials by nationality. Other includes clinical trials in the countries of Brazil, Denmark, Finland, Netherlands, Spain, and the West Indies. (B) Psychedelic drugs under analysis in each clinical trial. (C) Type of clinical trial. (D) Stage of currently reported clinical trials underway.

1 and 2 refer to trials including patients in both phase 1 and phase 2, respectively. N/A refers to trials with no listed phase. Other refers to exploratory trials before phase 1.