We are running a randomised controlled trial of psilocybin therapy for treatment-resistant depression. This will be the largest clinical study of its kind and is taking place in a number of clinical trial sites across Europe and North America. The trial is a phase IIb dose-ranging study with 216 patients. If successful, it will be followed by phase III studies in which we will look at comparing the optimal dose of the psychedelic, mostly likely to placebo or standard of care.