It is culturally constructed, but not unnecessary. A crisis is a period in a person's life that lasts at least a year during which there is an unusual level of emotional instability, negativity, and crucially, major changes. This is important because right now, when you diagnose mental health problems, where you are in life doesn't really come into it. Psychologists are saying that it should.

In your 20s, crises tend to be about whether you are making the correct decisions for the rest of your life, namely in your job and relationship. In your 30s, work-related issues and break-ups feature prominently. In your 40s, for women bereavement is often an issue. For men, it is still to do with their job but it has moved to "Holy crap, I've got a lot to do". In your 50s, you get features of both early and later life crises - bereavement and ill health. And that continues in your 60s, with retirement-related issues and heightened awareness of mortality.

The concept of a midlife crisis is a well known one perpetuated by books and films. And recently the idea of a quarter-life crisis, between 20 and 30, has also gained a fair amount of media coverage. But there's a surprising lack of robust research on these events, and almost none on later life crisis.

It is culturally constructed, but not unnecessary. A crisis is a period in a person's life that lasts at least a year during which there is an unusual level of emotional instability, negativity, and crucially, major changes. This is important because right now, when you diagnose mental health problems, where you are in life doesn't really come into it. Psychologists are saying that it should.

Half the people said that their lives had become better after a life crisis as a result of changes they made; some said the benefits and downsides balanced each other out; a smaller proportion said they never really recovered.

At any decade in your life, our results suggest that there is a 40 to 50 percent chance of having a life crisis. There's a slight increase with age and in general women tend to experience more than men - but that could be because they may be more open to admitting that they have had a hard time.