After years of setbacks, the announcement of the first drug to slow the brain's decline in Alzheimer's is being hailed as "momentous". What makes this breakthrough different? To study the effect of the environment on our health, scientists sometimes have to look to the past. We hear from the author of a study which has uncovered how the worst recession in US history may leave an indelible mark on how well people age. Claudia Hammond’s guest this week James Gallagher, the BBC's health and science correspondent, looks at a new single-dose treatment for sleeping sickness and claims it could help to eradicate transmission of the disease by 2030 and why monkeypox is being renamed. Presenter: Claudia Hammond Producer: Gerry Holt (Picture: Human brain scan in a neurology clinic. Photo credit: Andrew Brookes/Getty Images.)