(Reuters Health) – While army suicides have historically decreased during wartime, that trend appears to have reversed in recent decades, a new study of U.S. records finds.

Researchers poring over nearly 200 years of data found that unlike earlier times when there was a decline in suicide rates among U.S. Army soldiers during and just after wars, the rate has risen significantly since 2004, according to the report in JAMA Network Open.

The researchers can't explain the change – or the decline in previous eras during wartime – but they believe documenting the trends might lead to a better understanding of the underlying causes of military suicides.

“As a historian I would say it's impossible to solve the problem until you try to understand the history of it,” said study leader Jeffrey Smith, chair and associate professor in the history department at the University of Hawaii, Hilo. “We're hoping that gaining an understanding of history will help us in the fight to reduce the tragedy of military suicide.”

While the military suicide rate was markedly higher in the 1800s than today, it reached an all-time low just after World War II. “Then (it) remained at a low level until this period of open-ended wars,” Smith said. “We're hoping in follow-up studies to parse out the chronic and acute factors that cause military suicide.”

To learn more about historical trends in military suicides, Smith and his colleagues extracted data from U.S. Army Surgeon General reports and other government publications as well as medical journal articles published between 1840 and 2018.

Rates of suicide increased starting in 1843, peaking at 118.3 per 100,000 soldiers in 1883 (in a force of about 23,000 service members, the authors note). The rate then decreased in three successive waves, each corresponding with one of three wars: the Spanish American War (1898), World War I (1914 to 1918) and World War II (1939 to 1945).

The final years of WWII had the lowest rate of Army suicides, at 5 per 100,000 in 1944 and 1945. During the next few decades the rate was relatively stable, ranging from 10 to 15 per 100,000. It ticked up slightly at the end of the Vietnam War in 1975, to 18 per 100,000 soldiers. Then the rate started increasing during the Afghanistan and Iraq Wars, and from 2008 to the present, has ranged from 20.2 to 29.7 per 100,000. The peak of 29.7 was reached in 2012.

“It's interesting to note,” Smith said, “the military didn't take much in the way of active measures to decrease the number of suicides until World War II.”

The findings among military personnel mirror what's been happening in the general population, said Dr. Paul Nestadt, an assistant professor of psychiatry at the Johns Hopkins School of Medicine and the Johns Hopkins Bloomberg School of Public Health in Baltimore, Maryland, who wasn't involved in the study.

“In the general population there has been a 30% increase in suicide over the same last 17 years,” Nestadt said.

One hopeful sign is that once the military began to focus on reducing suicides, the rates actually fell, Nestadt added. “It may mean that when we do try to address it, the rates may be reduced,” he said.

SOURCE: and JAMA Network Open, online December 13, 2019.