Neurotic people—those who are prone to guilt, anger and anxiety—tend to be unhappy.
But some economists, unconvinced that there is a direct relationship between money and well-being, have decided to go to the nub of the matter and measure happiness itself.
Women, by and large, are slightly happier than men.
But they are also more susceptible to depression: a fifth to a quarter of women experience depression at some point in their lives, compared with around a tenth of men.
The academics quoted lyrics written by Pete Townshend of The Who when he was 20: “Things they do look awful cold / Hope I die before I get old”.
They pointed out that Mr Townshend, having passed his 60th birthday, was writing a blog that glowed with good humour.