France, Jan. 30 -- When Marie Mallevialle arrived at the Geneva University Hospital in 2023, she feared she was "losing her mind".

Two years earlier, the Franco-Swiss woman had lost her son to a brain tumour. "I was sleeping maybe an hour a night. I had dissociation, lots of flashbacks and reliving," she explained.

Doctors diagnosed post-traumatic stress disorder. Eye movement desensitisation and reprocessing therapy helped her work through her traumatic memories, but despite medication, the insomnia continued and the sadness remained overwhelming.

"I was stuck in the past," Mallevialle said.

While researching her condition, she came across psychedelic-assisted psychotherapy, where patients receive substances such as LSD or psilocybin...