(FILES) This file photo taken on April 19, 2016 shows marijuana plants under grow lights at Alternative Solutions, a DC area medical marijuana producer in Washington, DC. The US Drug Enforcement Administration on August 11, 2016 said it was again denying requests to allow the use of marijuana for medical purposes. The decision keeps a growing number of US states at odds with federal law, as half have enacted laws allowing access to cannabis for medical purposes. However, the federal government will allow an expansion of marijuana research, letting organizations apply for permission to grow marijuana for use in studies. / AFP / Brendan Smialowski
