FILE - In this Tuesday, April 7, 2015, file photo, Marine veteran Logan Edwards holds a sign to show support for cannabis for post traumatic stress disorder sufferers, outside the State Capitol in Des Moines, Iowa. Twenty-eight states plus the District of Columbia have enabled the use of marijuana to treat PTSD, and the number has doubled just in the last two years amid increasingly visible advocacy from veterans' groups. (Michael Zamora/The Des Moines Register via AP)