Australians overall are a happy bunch of people but suicidal thoughts are plaguing four per cent of the population, or half a million people, according to the new Black Dog Index designed to measure mental health.

The index was developed at the UNSW-affiliated Black Dog Institute and aims to calculate levels of happiness while also looking at levels of depression, anxiety and suicidal thoughts.

The index shows the happiest people are older, married, tertiary educated and earning more than $90,000 a year. But depression is strongly linked with divorce. It also shows four per cent of respondents were actively troubled by suicidal thoughts.

Black Dog Institute Director, Professor Helen Christensen says as well as giving a snapshot of rates of mental illness, the index will provide information about how to improve mental health and reduce suicide.

“It’s my hope that new programs like the Black Dog Index will improve public awareness about suicide and help those people who feel life isn’t worth living to contact Lifeline, their GP or a friend or family member to talk about it because help is available,” Professor Christensen says.