Many Australians have no or limited understanding of what schizophrenia is, according to a new survey.

Patricia Sutton says when some people find out her two sons have schizophrenia, their first question relates to violence.

"But you couldn't meet more caring, sympathetic and gentle people than my two sons," the Adelaide mother told AAP.

She more than agrees with the findings of a new survey showing 40 per cent of Australians have no or limited understanding of what schizophrenia is, yet almost a quarter know someone with the illness.

If diagnosed with the illness, 84 per cent of respondents said they wouldn't tell their boss, with half fearing they would be judged or miss out on job opportunities.

The April survey of 1000 people also showed that about half of carers had lost friends, had relationships break down or experienced family issues due to looking after someone with schizophrenia.

Mental Illness Fellowship of Australia (MIFA) CEO David Meldrum said the survey highlighted the need to address the stigma surrounding schizophrenia and to better support carers.

A 2010 profile found that about 15 per cent of Australian adults, or nearly 2.4 million people, act as carers of those living with a mental illness.

Ms Sutton and her husband Keith have provided daily support for their sons, one of whom lives at home, for the past 23 years.

Ms Sutton, who has become an advocate for people with mental illness, says one of the great myths about schizophrenics, perpetrated in the media, related to them all being violent.

And she agrees it's easy for carers to lose friends and become isolated.

"I don't think other people really get it, how disabled my sons are, how much is involved in their care," she said.

She spoke of the need for a wide variety of good quality accommodation options for those with schizophrenia and for more research on better treatment.

The survey was commissioned by MIFA and Janssen Australia.