Mental health and drug use may not be the first issues you think of when considering who to vote for in the primaries or this fall. But the failure of the war on drugs and the best ways to respond to addiction , are important issues for many of the 2016 presidential hopefuls, so it's good to know what they've said on the topic.During a Democratic primary debate in January, Vermont Sen. Bernie Sanders and former Secretary of State Hillary Clinton spoke candidly about America's heroin epidemic. The national response to issues of addiction became a prime focus of the debate, and the candidates shared their plans for addressing the United States' drug problem. Both candidates argued that heroin addiction should be treated first and foremost as a mental illness, rather than as a crime. At GOP primary debates, the Republican candidates have spoken about drugs as well.Addiction and mental health — in particular, a growing national opioid epidemic — were major issues for voters ahead of the Feb. 9 New Hampshire primary, and remain big ones in this year's presidential election. Candidates on both sides of the aisle have spoken out in favor of treating people with addictions with compassion rather than treating them like criminals. As New Jersey Gov. Chris Christie stated in October , "it can happen to anyone" — and we need to give people who struggle with addictions the respect and support they deserve.We've rounded up some of the most memorable statements the 2016 candidates from both major parties have made on the campaign trail so far.