NEW in Understand - The Trip

The story of psychedelics. It's a unique moment. After decades of taboo and blanket illegality, policymakers and research institutions are taking these substances seriously. As a new dawn of psychedelic treatment beckons, Tim Hayward makes a personal journey into how we got here and where this is all heading.Understand from BBC Radio 4 - unravelling the complexities of the biggest stories and subjects that really matter right now.