Mid-Life Crisis is Universal?

This article in The Financial Times discusses a recent study that claims mid-life crisis is universal.

I found this article to be interesting on a number of levels. First, it's interesting that women appear to have the crisis earlier in life. I wonder if there's a correlation between dwindling biological reproductive prospects and the depression of mid-life crisis.

Second, why are economics professors doing a study on mid-life crisis?

Third, both of the readings from the classes I'm taking referenced how perspectives on aging have shifted since gerontology began. The initial belief was that as we age, we disengage from society and life. Two newer perspectives are that we either have successful aging, wherein we are active and get more involved in life after retirement, or that we simply experience an extension of ourselves throughout the life spectrum. The quote below from the article seems to reference this last perspective as having been a point now refuted by the study:

"...the findings contrasted with many previous studies and with applied psychology textbooks – suggesting that, on average, our mood stays relatively consistent as we age."

The article also gives a few descriptions of the aging process that are very interesting, again, considering that the observations are coming from economists:

The most likely explanation, the researchers speculate, is that people “learn to adapt to their strengths and weaknesses, and in mid-life quell their infeasible aspirations”. Minor contributing factors might include a “selection effect”, with people living longer if they are cheerful than miserable, and – towards the end of life – a “comparison process” in which people count their blessings as they see their old friends dying off.

“For the average person in the modern world, the dip in mental health and happiness comes on slowly,” said Prof Oswald. “Only in their 50s do most people emerge from the low period. But, encouragingly, by the time you are 70, if you are still physically fit then on average you are as happy and mentally healthy as a 20-year-old. Perhaps realising that such feelings are completely normal in mid-life might even help individuals survive this phase better.”