It's a sad fact that suicide is the second leading cause of death among people ages 15 to 24. Even sadder: LGBTQ youth have an increased risk of suicide attempts. A new study suggests, however, that same-sex marriage policies are associated with a decrease in teen suicides attempts overall.It's not known why LGBTQ adolescents have higher rates of attempted suicide but stigma could be one reason. Researchers from the Johns Hopkins Bloomberg School of Public Health argue that policies against gay marriage are a form of structural stigma; they imply that same-sex couples do not deserve the same rights as opposite-sex couples. So for a new study in JAMA Pediatrics, they estimated the association between same-sex marriage policies on the state level and the proportion of young people attempting suicide.They used data from the state-level Youth Risk Behavior Surveillance System collected between 1999 and 2015 which includes mostly students in public schools. During that time, there were 32 states that implemented policies permitting same-sex marriage. So they looked at changes in suicide attempts among students before and after those policies were put in place as well as changes in attempted suicides in 15 states without policies that allow gay marriage. (Only 47 states conduct YRBSS surveys, which is why the number doesn't add up to 50.) All told, the data set included nearly 763,000 high school students, 231,000 of whom identified as LGBTQ.Before same-sex marriage policies were implemented, 8.6 percent of high schoolers and 28.5 percent of self-identified LGBTQ students across all states said they had attempted suicide in the past 12 months. They found that same-sex marriage policies were associated with a statistically significant 0.6 percentage point reduction in attempted suicides, so in the 32 states that permitted same-sex marriage, the attempted suicide rate was 8 percent, not 8.6 percent. (And, yes, they controlled for baseline state differences in suicide attempts.) That decrease works out to be a 7 percent reduction in the proportion of students attempting suicide and the effect was concentrated among LGBTQ students. They estimated that, every year, same-sex marriage policies would be associated with 134,000 fewer adolescent suicide attempts.This analysis shows correlation, not causation, but the authors note that the mental health consequences of these policies are worth considering. Their work builds on prior research which found that same-sex marriage bans were associated with increased diagnoses of psychiatric disorders in LGBTQ people and that medical and mental health care costs for gay and bisexual men decreased after Massachusetts implemented a same-sex marriage law. "As countries around the world consider enabling or restricting same-sex marriage, we provide evidence that implementing same-sex marriage policies was associated with improved population health," they concluded.