Suicides are rising in the United States, and no one really knows why

Suicide in the US is on the rise. What's more, suicide rates are increasing for both men and women in every age group, except for those over 75.

New data from the Centers for Disease Control and Prevention shows that suicide rates have steadily increased from 1999 to 2014, increasing in total by 24 percent.

To put it another way, in 1999, 10.5 deaths per 100,000 deaths for a specified age group were related to suicide. By 2014, that number had risen to 13.

When I talked with Sally C. Curtin, a statistician at the CDC and one of the authors of the report, she said she was surprised that suicide rates had increased nearly across the board. "You can’t pinpoint it to one group really," said Curtin about the upward trend. Even more worrying, starting in 2006, the annual percent increase in suicide rates climbed from 1 percent to 2 percent.

Suicide is currently one of the 10 leading causes of death. And for those between the ages of 10 and 34, it's the second most common cause of death after accidents.

But from 1986 to 1999, suicide rates were actually in decline.

Figuring out why suicide happens is hard at the national level

Dr. Alex Crosby, who heads up a branch of the violence prevention program at the National Center for Injury Prevention and Control, said that while we know a lot about what caused individual suicides, it's very hard to explain trends at the national level.

"We know about risk factors like psychiatric illnesses or a history of substance abuse, but we don't know the exact mixture," said Crosby. "It's hard to figure out what changed during that time period to have the rate go down and then go back up."

Crosby said the downturn of the economy with the recession in 2007 could have contributed to the increase in suicide rates. But he stressed that the increase in the suicide rate began in 2006, before the start of the recession, and has continued to hold firm at 2 percent per year despite the recession officially ending in 2010.

Women had a greater increase in suicides, but men are still three times more likely to kill themselves

Historically, men have significantly outnumbered women in suicide deaths. This still holds true even though women outnumber men in suicide attempts.

But from 1999 to 2014, the gender gap in suicide rates narrowed. However, men still committed more than three-fourths of the reported suicides in 2014.

For women between the ages of 10 and 14, the rate of suicide tripled, and as Curtin explained, this was the biggest increase of any group.

But Curtin also cautioned me to keep these numbers in perspective, as the number of suicides in women age 10 to 14 represent a tiny fraction — roughly 1.5 percent—of all suicides by women.

For men, suicide rates still remained highest among men 75 and over, but this demographic was also the only group to experience a percent decrease from 1999 levels.

Meanwhile men aged 45 to 64 experienced the largest percent increase in suicide deaths — 43 percent since 1999. This age group also experienced the second-largest percent increase for women — 63 percent.

For both men and women the greatest number of suicides occur at middle age, with it skewing slightly older for men.

Suicide is preventable. We need to better help vulnerable populations

For instance, we know that some of the most effective strategies for preventing suicide include easy access to clinical care and family and community support. But in my conversation with Dr. Crosby, he said that one of the most difficult things about suicide prevention at the public health level is that its causes are so varied.

Unlike heart disease where the causes are straightforward and well known — high blood pressure, high cholesterol or cigarette smoking to name a few — determining the factors that contribute to suicide is challenging.

"Trying to measure the risk of suicide due to psychiatric illnesses, previous victimization, or substance abuse is a challenge for the field," said Crosby. "But we do know enough about successful prevention programs that we can be doing more for some of the vulnerable populations."

Crosby cited the work of the National Action Alliance for Suicide Prevention as an example of a private-public partnership working to combat suicide at the community level and to better research and understand the causes of suicide at the national level.

If you are considering suicide, please seek help through the national suicide prevention lifeline at 1-800-273-8255.