Middle age is often seen as life's pivot point. A hill has been climbed and the view over the other side is unsettling. As Victor Hugo said: "forty is the old age of youth" and "fifty the youth of old age".
When Jonathan Rauch fell into the doldrums in his 40s, he had no idea why. Life was good: he had a successful career, a solid relationship, good health and sound finances. Then he learnt about the happiness curve and it all became clear.
A mid-career crisis can happen to anyone. It can hit even those who objectively have the most fulfilling jobs. When it does, it inflicts pain on the individual suffering it and causes productivity losses for employers. Yet, the phenomenon remains stigmatized and under-researched, leaving crucial questions unanswered. What are the causes?