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According to a large, national survey, about 6% of adolescents admit to attempting suicide at least once in the past year. Among adolescents who identify as homosexual or bisexual that number is 29%.  Why the difference? The thought is that the stigma surrounding being a sexual minority is simply incredibly stressful. But would the legalization of same-sex marriage, by perhaps reducing that stigma, also reduce suicide rates? According to this study, appearing in JAMA Pediatrics, the answer is a qualified yes.

The authors used data from a national survey called the Youth Risk Behavior Surveillance System, including responses from around 750,000 adolescents. They found that self-reported suicide attempts decreased by around 0.6% after the introduction of same-sex marriage laws in states that had them, compared to essentially flat rates in other states.  Among adolescents who identify as sexual minorities, the rate decreased by 4%.

We’ll touch on what these numbers mean, but first, is self-reported suicide attempt a perfect marker of actual suicide attempts? Almost certainly not, but no one has been able to come up with a better marker at this point. Further, one could argue that we should be more interested in the actual suicide rate, which is not captured by these surveys for rather macabre reasons. But keep in mind that the single largest predictor of successful suicide is suicide attempt.

Now, the authors didn’t simply look at the year before and after legalization of same-sex marriage, they actually modeled the trends of suicide attempts on a state-by-state basis.

You can see from the above figure that attempted suicide rates prior to legalization were pretty flat, on average. But on a state-to-state level there could still be important differences. What this analysis does then, is compare the actual attempted suicide rate to a rate predicted by a linear model. This is an imperfect analysis, but probably better than just looking at raw numbers.

I also want to mention their sort of cute sensitivity analysis wherein they looked at the rate of change in self-reported carrot consumption before and after same sex marriage legalization. That the carrot consumption rate was stable implies, I guess, that overall healthful behaviors hadn’t been effected that much.

Do these small effects matter? Well, the authors calculate that these reductions would correspond to 134,000 fewer adolescent suicide attempts every year.

Now, the cynics might be asking why we should care. After all, marriage equality is the law of the land. I think what this study shows us is how policy can have effects well beyond what was intended. Effects we need to consider, discuss, and proactively monitor. If changing a few marriage laws can have an effect on adolescent suicide rates, an undertaking like the total revamping of the health care system is bound to have effects that are even less predictable.