Using data on 2 million people, from 80 nations, researchers from the University of Warwick and Dartmouth College in the US have found an extraordinarily consistent international pattern in depression and happiness levels that leaves us most miserable in middle age.
Their paper entitled "Is Well-being U-Shaped over the Life Cycle?" is to be published shortly in Social Science & Medicine, the world's most-cited social science journal. The researchers found happiness levels followed a U shaped curve, with happiness higher towards the start and end of our lives and leaving us most miserable in middle age. Many previous studies of the life-course had suggested that psychological well-being stayed relatively flat and consistent as we aged.
Using a sample of 1 million people from the UK, the researchers discovered that for both men and women the probability of depression peaks around 44 years of age. In the US they found a significant difference between men and women with unhappiness reaching a peak at around 40 years of age for women and 50 years of age for men.
They found the same U-shape in happiness levels and life satisfaction by age for 72 countries: Albania; Argentina; Australia; Azerbaijan; Belarus; Belgium; Bosnia; Brazil; Brunei; Bulgaria; Cambodia; Canada; Chile; China; Colombia; Costa Rica; Croatia; Czech Republic; Denmark; Dominican Republic; Ecuador; El Salvador; Estonia; Finland; France; Germany; Greece; Honduras; Hungary; Iceland; Iraq; Ireland; Israel; Italy; Japan; Kyrgyzstan; Laos; Latvia; Lithuania; Luxembourg; Macedonia; Malta; Mexico; Myanmar; Netherlands; Nicaragua; Nigeria; Norway; Paraguay; Peru; Philippines; Poland; Portugal; Puerto Rico; Romania; Russia; Serbia; Singapore; Slovakia; South Africa; South Korea; Spain; Sweden; Switzerland; Tanzania; Turkey; United Kingdom; Ukraine; Uruguay; USA; Uzbekistan; and Zimbabwe.
The authors, economists Professor Andrew Oswald from the University of Warwick and Professor David Blanchflower from Dartmouth College in the US, believe that the U-shaped effect stems from something inside human beings. They show that signs of mid-life depression are found in all kinds of people; it is not caused by having young children in the house, by divorce, or by changes in jobs or income.
University of Warwick Economist Professor Andrew Oswald said:
"Some people suffer more than others but in our data the average effect is large. It happens to men and women, to single and married people, to rich and poor, and to those with and without children. Nobody knows why we see this consistency."
"What causes this apparently U-shaped curve, and its similar shape in different parts of the developed and even often developing world, is unknown. However, one possibility is that individuals learn to adapt to their strengths and weaknesses, and in mid-life quell their infeasible aspirations. Another possibility is that cheerful people live systematically longer. A third possibility is that a kind of comparison process is at work in which people have seen similar-aged peers die and value more their own remaining years. Perhaps people somehow learn to count their blessings."
"It looks from the data like something happens deep inside humans. For the average person in the modern world, the dip in mental health and happiness comes on slowly, not suddenly in a single year. 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 realizing that such feelings are completely normal in midlife might even help individuals survive this phase better."
The research analysed information on 500,000 randomly sampled Americans and West Europeans from the General Social Surveys of the United States and the Eurobarometer Surveys. The authors also looked at the mental health levels of 16,000 Europeans, the depression and anxiety levels among a large sample of U.K. citizens, and data from the "The World Values Survey" which gives samples of people in 80 countries.