A study by Cornell University psychologists has found that retirement can spark marital discord and depression.

Jungmeen Kim and Phyllis Moen, who studied 534 married men and women between the ages of 50 and 74, found that men who retired while their wives were still working showed a higher level of marital stress then newly retired men whose wives did not work.

The happiest men were the ones who found another job and whose wives were not working.

"Those who are retired and reemployed report the highest morale and lowest depression," said Kim.

Men who stay retired fare worst in terms of depression and low morale.

Women also at risk

Among women, starting retirement posed a risk of depression, especially if their husbands were still working - but getting another job did not help.

This contradicts the findings of other studies, which have found that when both partners were retired, they are happier because they can have more time together and do things they've long to do for years and years.

Ms Kim said that men who go back to work after their retire usually take a job because they want to.

"When retired women rejoin the work force, they usually have to do it for financial reasons," she said. Other research suggests that the elderly are the most vulnerable to depression.