This past week, the Pres. Donald Trump Administration announced it would not turn as blind of an eye toward legalization of ganja use in the states. The previous administration essentially had told attorney generals not to prosecute usage in states that decriminalized this. Now, orders have gone out unbinding prosecutors to that.
That means states which, under their law, have decriminalized possession of small amounts of weed, their citizens face increased chance that the federal government will bring them up on charges. Where medical marijuana use has legal status, technically those who use it in any form have a greater risk of arrest for that.