Your 20s are your happiest years. (Stock image) / Christopher Furlong/Getty Images

Happiness decreases from your early 20s and only increases when you reach 65

People are happiest during their 20s, a new study suggests.

Dr Ioana Ramia, a researcher at the University of New South Wales, said her research found life satisfaction follows a u-curve, in that it "decreases from the early 20s, plateaus for about 40 years and then increases from about 65 up".

MedicalXpress reported that Ms Ramia, who was speaking at the Australian Social Policy Conference, said people are at their happiest again around the age of 80.

Couples reported their highest satisfaction just before having their first child, followed by a dip from the child's first year of life through to around age six, when the child started school.

Ms Ramia attributed the amount of importance placed on money and jobs as a possible reason why people become unhappier during their middle years.

"At this time happiness is at its lowest and it only starts to increase when people start focusing on other things," she said.

The study also found quality of housing was of little importance to the overall happiness of younger people, who were more concerned about living closer to work, entertainment and friends.

A greater emphasis on housing quality was seen in those who are middle aged and beyond, who also had a greater focus on their neighbourhood and the community.

The study drew data from the national Household, Income and Labour Dynamics in Australia survey.

Although her research examined the ages at which people are happiest, Ms Ramia said the peaks at young and old age remain poorly understood and would be a challenge for future research to examine.