During the early weeks of the pandemic, Tim Hayward spent 14 days in a coma. He remembers this time vividly – his days and nights filled with strange, incandescent visions and hallucinations. That experience is something he would never choose to revisit but, around the world, large numbers of people are deliberately seeking out powerfully altered states.

In this ten-part series, Tim sets out to better understand a group of substances that induce altered states: psychedelics.

There’s been a surge of interest in their therapeutic potential for various mental health conditions - as well as a range of other clinical possibilities. As research around the world ramps up after years of taboo and prohibition he tries to get to grips with - or at least get a clearer sense of - how science, culture, politics and business might all interact in this changing psychedelic landscape, and what it all might mean.

He also explores what might be happening in the brain during a trip and whether, by studying psychedelics, we might uncover more about consciousness, imagination and even the mysteries of reality itself.

In this episode, Tim travels back in time to a Victorian pharmacy, drinks a lot of coffee, uncovers some pioneering psychedelic research in 1950s Canada - and discovers a nurse who was there.

Contributors: Erika Dyck, historian of psychedelics, University of Saskatchewan Mike Jay, author and cultural historian Kay Parley, former nurse Saskatchewan Hospital, Weyburn, Canada Andrew Penn, psychiatric nurse practitioner and psychedelics researcher, University of California San Francisco School of Nursing

Presenter: Tim Hayward Series Producer: Richard Ward Executive Producer: Rosamund Jones Editor: Kirsten Lass Written by Tim Hayward and Richard Ward Sound Design and Mixing: Richard Ward Researcher: Grace Revill Voiceover Artist: Sandra-Mae Lux Special thanks to Zoë Dubus Commissioning Editor: Daniel Clarke A Loftus Media production for BBC Radio 4