The concept of the "mid-life crisis" has been around for quite sometime, yet whether it was an actual thing or just an excuse for people to tool around in sports cars has remained unclear.

Past evidence for the mid-life crisis relied on cross-sectional survey data, or the examination of people's happiness at different ages. However, researchers recently tracked happiness levels of tens of thousands of people in three countries over several decades, marking the first time the mid-life crisis has been examined in this way.

"We have identified a clear 'U-shape' in human well being," said researcher Dr Terence Cheng, from the University of Melbourne's Institute of Applied Economic and Social Research. "The jury's now in. People really do experience mid-life crises."

The study was completed with assistance from the University of Warwick and the London School of Economics, and published as a working paper by the German-based Institute for the Study of Labor.

Researchers analyzed data from "nationally representative" surveys in Australia, Britain and Germany.

"What is interesting is the consistency of the results in all of the three countries we examined. Human happiness hits the lowest point around the ages of 40 to 42," Dr Cheng said. "Indeed all the more intriguing is that the U-shape pattern has been recently observed in research on great apes. Perhaps we are more similar than we think?"

The professor noted tracking happiness changes "over time" significantly adds to the accuracy of the study.

"We looked at the well-being of 'Mr. Jones' at age 35, 45, 55, and so on. This is important as the U-shape finding therefore does not arise from variations across different people, but rather within individuals," he noted.