A dancer on ecstasy shows his skills with glow sticks at a club in Washington, DC – but will the drug affect his health in the long term? (Image: Scott Houston / Sygma / Corbis)

THEY called it the second summer of love. Twenty years ago, young people all over the world donned T-shirts emblazoned with smiley faces and danced all night, fuelled by a molecule called MDMA. Most of these clubbers have since given up ecstasy and are sliding into middle age. The question is, has ecstasy given up on them?

Enough time has finally elapsed to start asking if …