Same-sex marriage legalisation may cut teen suicide rates

Legalising same-sex marriage may significantly reduce the rate of suicide attempts among high school students, with a higher reduction among gay, lesbian and bisexual adolescents, a new study has found.

The researchers from the Johns Hopkins Bloomberg School of Public Health in the US estimated that state-level, same-sex marriage policies were associated with more than 134,000 fewer adolescent suicide attempts per year.

The study compared US states that passed laws allowing same-sex marriage through January 2015 to states that did not enact state-level legalisation.

A US Supreme Court decision had made same-sex marriage federal law in June of 2015.

The findings show the effect that social policies can have on behaviour, researchers said.

"These are high school students so they aren't getting married any time soon, for the most part," said Julia Raifman, a post-doctoral fellow at the Bloomberg School.

"Still, permitting same-sex marriage reduces structural stigma associated with sexual orientation," said Raifman.

"There may be something about having equal rights - even if they have no immediate plans to take advantage of them - that makes students feel less stigmatised and more hopeful for the future," she said.

In the study, 29 per cent of gay, lesbian and bisexual high school students reported attempting suicide in the previous year compared to six per cent of heterosexual teens.

For the study, researchers analysed data from 32 of the 35 US states that enacted same-sex marriage policies between 2004 to 2015.

They used data from 1999 to 2015 to capture trends in suicide attempts five years before the first same-sex marriage policy went into effect in Massachusetts.

They were also able to compare data with states that did not enact same-sex marriage laws. They conducted state-by-state analyses, comparing, for example, suicide attempt rates in a state like Massachusetts before same-sex marriage was legalized to the period right after.

State same-sex marriage legalisation policies were associated with a seven per cent reduction in suicide attempts among high school students generally.

The association was concentrated in sexual minorities, with a 14 per cent reduction in suicide attempts among gay, lesbian and bisexual adolescents.

The effects persisted for at least two years. The states that did not implement same-sex marriage saw no reduction in suicide attempts among high school students.

It is unclear whether the political campaigns surrounding same-sex marriage legalisation were behind the reduction in suicide attempts or the laws themselves.

Still, they found that the reduction in suicide attempts was not realised until after a law was enacted. In a state that would go on to pass a law two years in the future - when there was likely to be much conversation in the public about it - suicide attempts remained flat before passage.

The research was published in the journal JAMA Pediatrics.