Two Theories on Why Suicide is Rising in America and Falling In Europe
Suicide is now one of the leading causes of death in America, eclipsing both homicide and car accidents. And its risen by more than 30% over the last 15 years. Most of Europe, on the other hand, has experienced a substantial decrease in suicide, about 20% overall.
There is little research into why the difference exists, but Steven Stack, Professor of Criminal Justice at Wayne State University has looked at the studies that have been done and posits two theories.
From Science Alert: The Decrease in America's Social Safety Net - "There is evidence that rising suicide rates are associated with a weakening of the social norms regarding mutual aid and support.
In one study on suicide in the U.S., the rising rates were closely linked with reductions in social welfare spending between 1960 and 1995.
Income inequality - 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 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 ensuing economic strain is a risk factor for suicide. As U.S. income inequality has been increasing, one study found an increasing percentage of midlife suicides reportedly associated with financial problems."

Professor Stack admits that a lot more research is needed to pinpoint the causes of America's increasing suicide problem, but offers his theories as a starting point for future study.