During World War I, many scientists believed that shell shock, now known as post-traumatic stress disorder, was a physical illness caused by experiences in the trenches. Over 300 British soldiers were executed for shell shock during the war. Common symptoms included fatigue, headaches, sweating, nausea, insomnia, nightmares, confusion, and depression. Early attempts to treat soldiers involved giving them experimental medications, which often caused further harm or death. Prolonged exposure to life-threatening conditions in the trenches without relief took a severe psychological toll on soldiers. Shell shock has continued to affect veterans and the only effective treatment remains therapy.