The war cost the American people 125,000 of their sons. Fifty thousand men died in combat. Another 75,000 died from other causes, notably the influenza epidemic that struck in the closing months of the war. In eight weeks starting in September, influenza caused 300,000 deaths in the United States. A total of479,000 Americans died in 1 9 1 8 and 1 9 1 9, including 2,000 troops en route to Europe. An American Army of the Rhine, 16,000 strong in 1920, remained in Germany in the region around Trier and Coblenz to help enforce the peace treaty, its last unit leaving only in January 1923. Many Americans who had served in the war returned with lasting psychological difficulties. "War neurosis" (commonly known as shell shock) led to disability discharges for almost 42,000 servicemen. In early 1922 veterans' hospitals contained 9,000 patients suffering from service-connected psychological difficulties. Eighteen years later, the number of individuals hospitalized or otherwise being treated for this injury to the emotions remained the same. This suggests that there were vastly more former servicemen who suffered in silence or got care outside government channels.