A savage drug epidemic has seized New Hampshire, home of the presidential race’s first primary election. And that’s created a potent 2016 campaign issue—one that top candidates can’t afford to ignore.

In the past decade, the state government reports, the number of people admitted to state-funded treatment programs rose by 90 percent for heroin and 500 percent for prescription opiate abuse.

“We have in New Hampshire some of the highest per capita rates of addiction in the United States,” Tym Rourke, chairman of the New Hampshire governor’s commission on drug abuse, told The Daily Beast. “So we are very, very much at ground zero for addiction… Right now, we are having an overdose death every day.”

If a presidential candidate hopes to have sway over the state’s voters, Governor Maggie Hassan told The Daily Beast, they’re going to need to read up on heroin addiction.

“It’s going to be really important that all presidential candidates visiting New Hampshire be prepared on this issue, to understand how it’s wreaking havoc in our state,” she said. “You cannot go into a room in New Hampshire, of more than a couple of people, and not have them raise the issue of how substance abuse is impacting our state.”

“I think the candidates have come to New Hampshire surprised that in many of their first stops, substance abuse was a major issue for voters,” Rourke said.

Ted Gatsas is the mayor of Manchester, New Hampshire, a town of just over 110,000 people where 50 have died from heroin overdoses since January. Because of the state’s role in picking presidents, he has far greater sway than almost any other mayor of a comparably-sized town, and he’s using it to talk about the addiction issue.

In this cycle alone, he says, he has met with Jeb Bush, Chris Christie, Scott Walker, Rand Paul, Donald Trump, John Kasich, Lindsey Graham, George Pataki, and Bobby Jindal. And to each of them he has stressed that they need to be paying attention to the nationwide problem of heroin addiction more broadly, and specifically its effects on the Granite State.

“When they come into my office, that’s what I talk to them about,” Gatsas said. “It’s something that the entire country should be drawing attention to, because people are dying.”

Ohio Gov. John Kasich name-checked the mayor last week during a presidential forum.

“We have the mayor of Manchester, who’s fighting a tsunami here,” Kasich said. “I think it’s very important that with economic growth comes responsibility and ability to help people who live in the shadows, whether they’re mentally ill or drug-addicted.”

Hillary Clinton’s campaign has been reaching out to local leaders in addiction treatment.

“I really commend Hillary Clinton, who just as she started her campaign… really began to bring the public focus on this issue,” Hassan said. “I would encourage all of the other candidates for president to follow her lead and focus on how they’ll address the epidemic.”

The issue has already made its way into Republican presidential forums, debates, and town halls.

“The first question I was asked in my first town hall meeting was about the heroin epidemic,” former Florida Governor Jeb Bush told the New Hampshire Union Leader editorial board.

“You talk about New Hampshire for a moment. One of the stories that has not been as reported nationally, is the fact that many of the people who today are dependent on heroin, is because they became dependent on prescription opiates,” Senator Marco Rubio said, in an answer about why he doesn’t support legalizing marijuana, at a forum in New Hampshire last week.

New Jersey Governor Chris Christie recently visited a local treatment center. “New Hampshire’s got its issues, but so does New Jersey and so does Iowa, and places I’ve been visiting have all been experiencing the same thing. This is an epidemic in our country,” he said.

“In my own state as governor, it is a drug that you don’t take. It takes you,” Wisconsin Governor Scott Walker recently told WMUR, a New Hampshire news network. “This has become a major concern particularly in rural and in less densely populated areas. It's not just a drug problem in the big cities. That is all the more reason why we need to take major portions of our resources and send them from the federal government—from Washington—back to our states and local communities.”

More than 8,200 people died of heroin-related overdoses nationwide in 2013, the Centers for Disease Control and Prevention reported. And use of the drug has more than doubled among adults age 18-25 over the past 10 years.

Heroin is an opioid, the same general kind of drug used in many prescription painkillers, which are among the most commonly abused drugs in the country, according to the National Institute on Drug Abuse. If taken in amounts or ways other than prescribed, opioid pain medications like Oxycontin and Vicodin can have heroin-like effects: an initial euphoria, followed by a period of alternating between drowsiness and wakefulness.

The CDC notes that people who are addicted to prescription opioid painkillers are 40 times more likely to be addicted to heroin. Efforts to clamp down on prescription opioid painkiller abuse have partly—unintentionally—fueled the demand for heroin. Heroin is cheaper, and can often be obtained more easily, although illegally, than prescription drugs.

When New Hampshire clamped down on prescription drug abuse, local addicts turned to heroin, Rourke said. “This heroin epidemic has been a tsunami in health-care disasters 30 years in the making.”

But candidates have not yet gotten specific about how to deal with drug abuse. One potential reason for this is that treatment methods can be quite controversial, especially publicly-funded needle exchanges or more access to methadone, a drug used to help wean individuals off addiction.

“While Republican candidates brought this up during the debate, on the federal level the Republican Congress has moved to cut funding for substance abuse, and they also all are running against the continuation of the Affordable Care Act, which includes Medicaid expansion coverage for substance abuse and behavioral health,” Hassan said.

Republican candidates could turn to the Comprehensive Addiction and Recovery Act, a piece of legislation co-sponsored by New Hampshire Republican Senator Kelly Ayotte and a number of other senators from both parties. Of the senators who are running for president, only Lindsey Graham has signed on. The bill would authorize the federal government to award grants to address the opioid and heroin use epidemic.

“We’re facing a public health crisis in our state. We’ve had a dramatic increase in heroin and opioid deaths,” Ayotte told The Daily Beast. “This is a very big issue, and that’s why I think you see the presidential candidates who are campaigning in New Hampshire mentioning it, on both sides of the aisle.”

—with additional reporting by Alexa Corse