The way people care for themselves in midlife has a major impact on how happy they will be in their old age.
That means not smoking, keeping fit and staying mentally active, says Professor Brian Draper, a speaker at a Perth congress hosted by the The Royal Australian and New Zealand College of Psychiatrists.
It's also important for people to keep engaged with society after retirement, says the University of New South Wales and Prince of Wales hospital psychiatrist.
The biggest risk group for suicide in Australia is men older than 75.
"In older people depression is probably the major predictor of suicide, but quite a few victims have never had depression before. In many cases it is undiagnosed and nobody else knows about it," says Prof Draper.