The future of psychedelics is looking bright, after some dark times. Just two years ago, the US Food and Drug Administration (FDA) rejected an application to use MDMA — the active ingredient in the party drug ecstasy — to treat post-traumatic stress disorder. With that refusal, the whole field seemed to stall . But now, billion-dollar investments and more clinical-trial data suggest that the field is forging ahead.

The FDA refusal “stimulated a lot of thought and conversation”, says Rachel Yehuda, a neuroscientist at Icahn School of Medicine at Mount Sinai in New York City. “But it didn’t make people want to give up on these medicines. Everyone can see that loud and clear.”

In July, the drug giant Eli Lilly in Indianapolis, Indiana, announced plans to acquire AtaiBeckley, a psychedelic-medicine development firm in New York City, for up to US$3.8 billion.…