WASHINGTON (AP) – The Institute of Medicine recommended Friday that soldiers returning from Iraq and Afghanistan undergo annual screening for post-traumatic stress disorder and that federal agencies conduct more research to determine how well the various treatments for PTSD are working.

Of the 2.6 million service members deployed to Iraq and Afghanistan, it’s estimated that 13 percent to 20 percent have symptoms of PTSD.

Federal agencies have increasingly dedicated more resources to screen and treat soldiers, but considerable gaps remain, according to the Institute of Medicine, an independent group of experts that advises the federal government on medical issues. Its recommendations often make their way into laws drafted by Congress and policies implemented by federal agencies.