Our ability to be happy may be pre-determined by our genes
Momentous events in your life such as having children, or getting married, may make you happier, but only temporarily, say researchers.
Our basic happiness level essentially stays the same throughout adult life, the Economic Journal reports.
Economists from the UK, US and France based their conclusions on a 20-year analysis of the life satisfaction of hundreds of people from Germany.
Even after traumatic events, overall mood dipped but then recovered.
The study looked at a psychological process called "adaptation" - the way in which humans adjust to new circumstances, good or bad.
The German volunteers, aged between 18 and 60 at the start of the study, were then questioned again regularly over the following two decades and asked to rate their own happiness.
They were also asked to report any major events so that the researchers could plot the relationship between the event and overall levels of satisfaction.
They found that only unemployment gave a long-lasting decline in overall mood in the five years after the event.
In other traumatic events, such as widowhood or divorce, overall mood dipped, but then recovered.
For positive events, such as marriage or childbirth, the effect was equally transient - the researchers calculated that the happiness increase delivered by the birth of a child lasted for two years before the volunteers ratings were back to normal.
Dr Yannis Georgellis, a senior lecturer at Brunel University, and co-author of the report, said that it suggested that old adages such as "time heals" were true in many cases.
He said: "It's consistent with other findings that people recover from negative events very quickly - there was some literature on people who became paraplegic, who, when interviewed a few years later, had similar levels of happiness to those who had not been affected this way.
"Likewise, there are studies of lottery winners who are no happier in the long term."
Francois Moscovici, director of psychological consultancy firm White Water Strategies, said that there was plenty of evidence that people had a fixed, underlying "range" of happiness, which could be temporarily affected by major events, but not usually for long periods.
"There is the concept of a 'thermostat' of happiness - when a big event happens to you, whether it is positive or negative, the spring stretches, but returns back to its former state quite quickly."