Brain scanning experiments reveal how psilocybin works to relieve severe depression. Psilocybin is the psychedelic substance in 'magic mushrooms'. The psychoactive chemical is currently in clinical trials in the UK and US as a potential treatment for depression and other mental illnesses. Professor David Nutt of Imperial College London tells Roland about the research

Also in the show, worrying findings about the increase in premature deaths because of air pollution in growing cities in tropical Africa and Asia. An international group of climatologists has found that the tropical storms which struck Mozambique, Malawi and Madagascar in early 2022 had been made more intense by human-induced climate change. And astronomer David Jewitt used the Hubble telescope to measure the largest known comet in the solar system - it's huge at about 120 kilometres across.

(Image: Mexican Psilocybe Cubensis. An adult mushroom raining spores. Credit: Getty Images)

Presenter: Roland Pease Producer: Andrew Luck-Baker