United States army suicide rates have historically decreased during wartime.But a new study of U.S. records suggests that trend appears to have changed direction, with rates rising in recent years.Researchers examined nearly 200 years of U.S. army records and other information.They found that, in earlier times, there was a decrease in suicide rates among army soldiers during and just after wars.However, the researchers report that the rate has risen considerably since 2004.Their report appeared in JAMA Network Open, a publication of The Journal of the American Medical Association.The researchers cannot explain the change - or the decrease in earlier periods during wartime.But they believe documenting the trends might lead to a better understanding of the underlying causes of military suicides.Jeffrey Smith was the leader of the study.He heads the Department of History at the University of Hawaii, Hilo.Smith told the Reuters news agency that the increase in suicide ratesis impossible to solve until you try to understand the history of it."We're hoping that gaining an understanding of historywill help us in the fight to reduce the tragedy of military suicide," said Smith.The military suicide rate was markedly higher in the 1800s than in modern times.Then it reached an all-time low just after World War II,where it remained "until this period of open-ended wars," Smith added.Smith's team is hoping to launch other studies into the causes of military suicide.To learn more about trends in army suicide, they studied U.S. Army Surgeon General reports,other government publications and medical journals published between 1840 and 2018.Rates of suicide increased starting in 1843.The suicide rate reached its highest level, at 118.3 per 100,000 soldiers, in 1883.The rate then decreased in three waves, each linked with one of three wars:the Spanish American War in 1898, World War I and World War II.The final years of World War II had the lowest rate of Army suicides, at 5 per 100,000 in 1944 and 1945.From there, it changed little until the end of the Vietnam War in 1975,when it reached 18 per 100,000 soldiers.Then the rate started climbing during the Iraq and Afghanistan Wars."It's interesting to note ... the military didn't take much in the way of active measuresto decrease the number of suicides until World War II," Smith said.Paul Nestadt is an assistant professor of psychiatry at the Johns Hopkins School of Medicine in Maryland.He was not involved in the study, but he noted that its findings among members of the militaryare similar to what has been happening in the general population."In the general population, there has been a 30% increase in suicide over the same last 17 years," he said.Nestadt noted that one hopeful sign is once the military began to work on reducing suicides, the rates actually fell."It may mean that when we do try to address it, the rates may be reduced," he said.