Psychedelic drugs have long been been used for their mind-altering effects. Now, they are making their way into western medicine as a treatment for mental health disorders. From July, psychiatrists in Australia will be able to prescribe MDMA for post-traumatic stress disorder, making it the first country in the world to recognise psychedelics as medicines. The US could soon follow, with plans for the US Food and Drug Administration to be asked for approval to treat PTSD with MDMA this year. Ian Sample speaks to correspondent Hannah Devlin about how the science behind psychedelic therapy has progressed, and hears from Prof Celia Morgan about what treatment is actually like, what we know about the risks and what’s left to learn. Help support our independent journalism at theguardian.com/sciencepod