LGBTQI+ advocates say the findings have big ramifications for the highly-publicised religious freedoms debates.
The same-sex marriage postal service in 2017 led to increased levels of depression, anxiety and stress among LGBTIQI+ Australians, new research has found.
A University of Sydney survey of 1,305 LGBTQI+ Australians found exposure to negative marriage-equality sentiments was behind the increase.
“The findings highlight how political decision-making and legislative processes related to the rights of minority populations have the potential to negatively affect their mental health,” said Stefano Verrelli from the University of Sydney’s School of Psychology, the survey’s lead author.
The research also examined what helped protect people's mental health during the postal survey.
Family and friends openly supporting LGBTQI+ rights helped offset some people's negative mental health experiences, Mr Verrelli said, as did seeking help from mental health services.
“LGBTQI+ rights and mental health organisations have an important role to play by continuing their public support of minority issues.
"Their public messages of support appear to improve the psychological well-being of same-sex attracted people who require it most,” Mr Verrelli said.
It is important people reach out to friends and mental health services if feeling indisposed by future scrutiny, he said.
The findings come as debate rages over whether religious schools should be allowed to discriminate against students and staff on the basis of their sexuality.
A spokesperson for LGBTQI+ legal advocacy group Equality Australia, Aram Hosie, said people need to be aware of who their words may affect.
“It is incredibly important that people taking part in these debates be mindful about the potential mental health impacts on the people that they’re debating,” he told SBS News.
“The longer these debates go on the worse the impact on the mental health of those concerned."
Mr Hosie said the debates are “out of step” with what the Australian public thinks.
Almost three quarters of Australians believe students and teachers at faith-based schools should be legally protected from exclusion on their sexuality, according to Equality Australia’s own research.
“A vast majority of Australians, almost 70 per cent, support the protection of LGBTQI+ students and teachers to learn and go to work.”
"We really want to see politicians get a move on and make the legislated changes that reflect the majority of the population."
People seeking mental health support can contact Lifeline on 13 11 14 and Beyond Blue on 1300 22 4636.