Fig. 1. Acute subjective effects of N,N-dimethyltryptamine (DMT) over time.

The different intravenous dosing conditions of DMT were the following: Low infusion (0.6 mg/min), high infusion (1 mg/min), low bolus (15 mg) + low infusion (0.6 mg/min), and high bolus (25 mg) + high infusion (1 mg/min). The low and high bolus doses induced similar maximal drug effects on all four subjective effect scales, peaking within the first 2 min after intravenous bolus administration and decreasing relatively quickly within 10–15 min. The low and high infusions without a bolus dose induced “any drug effects” (A) and “good drug effects (B),” reaching a plateau after 30 min and remaining stable at the respective level until the end of the infusion at 90 min. After stopping the infusion, all drug effects rapidly and completely subsided within 15 min. Only minimal “bad drug effects (C)” and no “anxiety (D)” were induced by the infusions. Effects of the low and high bolus doses did not differ significantly, whereas the different infusion rates produced significantly different plateaus of “any drug effects” and “good drug effects.” Bolus doses were administered at t = 0. Infusions started at t = 1 min and lasted until t = 90 min. The data are expressed as the mean ± SEM in 27 participants. The corresponding maximal responses and statistics are shown in Table 1 and Supplementary Table S5.