[Editorial] Putting placebo effects in a new light

Placebo effects have puzzled and intrigued researchers for decades but, despite playing an important role in modern trial design and treatment development, they remain relatively mysterious. With the development of new treatments in psychiatry, especially psychedelic-assisted psychotherapy, placebo effects are under the spotlight. In this issue, The Lancet Psychiatry presents two Review articles by Matthew Burke and colleagues on reconceptualising placebo and nocebo effects.