The suicide rate rose by 3.7 percent from 2016 to 2017, contributing, with opioid deaths, to a drop in U.S. life expectancy. But both suicide and opioids may be linked to a higher-level cause: economic inequality. The link between inequality and suicide isn’t new, but it may be gaining in relevance given the increased inequality in the U.S. in recent decades.

Research has generally found that the higher the level of income inequality in the U.S. states, the higher the probability of death by suicide. According to social strain theory, when there’s a large gap between the rich and the poor, those at or near the bottom struggle more, making them more susceptible to addiction, criminality and mental illness than those at the top.

The official suicide rate may be too low, with opioid deaths classified as accidents that may not have been so accidental:

[Epidemiologist Ian] Rockett said he’s involved in a clinical trial at Harvard where researchers are interviewing people who survived overdoses. “[Researchers] asked them about if they were considering suicide at the time and there’s evidence that quite a few of them are,” he said.

And, Rockett points out, opioid addiction itself can be a symptom of economic inequality:

In West Virginia, for instance, loss of jobs in the coal industry has led to unemployment and underemployment that forces people into multiple jobs to make ends meet, he said. Construction or extraction industries jobs have high injury rates that can lead to addictions to opioids. “It’s not surprising, it’s tragic, actually, but growing inequality, under employment, unemployment, I think are major factors there,” he said.

Our economy is killing people, and the killer part is the part Republicans are trying to boost.