THIS YEAR, THE GOVERNMENT WILL SPEND A RECORD $4.6 BILLION to fight the nation’s opioid crisis—a 254% increase in spending over 2017—and it plans an even bigger outlay in 2019. Some of those funds will go to prevention efforts, others to addiction research, and one embattled slice will go to treating people with addictions by means of opioid-based medications, including methadone.

Still the most widely used intervention for people recovering from heroin and other opioid addictions, methadone combats cravings and withdrawal symptoms, which can be debilitating, and blocks the high of other opioid drugs. For decades, regular doses of methadone, administered daily in highly regulated clinics, have been the gold standard in treatment for chronic opioid addiction.

“The studies go back over 30 years, and the research is global,” says Mark Publicker, a Maine physician and past president of the Northern New England Society of Addiction Medicine. “Methadone is unequivocally an extremely effective treatment.”

But methadone is deeply unpopular. Critics these days, especially in the political sphere, view methadone treatment as replacing one drug with another, a bias that has limited government funding for new clinics. Only a handful of commercial insurance plans have recently begun paying for the treatment, and a dozen or so states, mostly in the Great Plains and the Southeast, have directed their Medicaid programs not to cover methadone therapy at all.

Many programs that use medication-assisted therapy, or MAT, for opioid addiction have shifted their preference to newer medications that require less clinician supervision. Naltrexone dampens the effect of opioids in the body and is not itself opioid-based. Buprenorphine comes with less risk of overdose than methadone.

Yet these other drugs, which are prescribed monthly or weekly, lack the supervision and counseling that come with methadone and may be less powerful in helping users overcome addiction. A 2014 analysis of several dozen studies comparing methadone to buprenorphine shows that although the medications are equally effective in treating immediate opioid addiction, methadone is superior when it comes to keeping patients in recovery over the long haul.

“Some people really need the daily structure and supervision required in methadone maintenance,” says Merideth Norris, a physician and addiction specialist in Sanford, Maine. “For others, like those who have built up a high tolerance for opioids through chronic use or high doses, methadone is the only addiction medication that works.”

The problem with methadone, says Norris, is that fewer local communities have the resources and the will to run the outpatient opioid-treatment programs that it requires. Norris served as medical director for a methadone center in Maine, which has one of the highest per-capita opioid prescription rates in the country and an average of more than one overdose fatality every day. But Medicaid cuts and “rock bottom” reimbursement rates forced that center, and others like it across the state, to shut down. “I’d already admitted nine people the day the announcement came,” Norris says. In its wake, a hundred of her patients had to compete for a short list of remaining resources in their communities.

An estimated 2.4 million people in the United States are addicted to opioids, but only about 400,000 of them get methadone therapy, through some 1,550 federally licensed programs. To put this in starker terms, the number of deaths from opioid overdose has grown by 200% over the past decade, but the number of people in methadone treatment has grown by less than 25%, says Mark Parrino, president of the American Association for the Treatment of Opioid Dependence in New York City.

The opening of new methadone clinics has been stalled partly by lack of funding. Yet there’s also the not-in-my-backyard problem. “Residents incorrectly worry that clinics might attract crime or drug users,” says Jason Kletter, president of BayMark Health Services in Lewisville, Texas, which operates 167 opioid treatment locations in 26 states. “But the science demonstrates that crime actually decreases when people with opioid-use disorder are in treatment.”

Most current methadone clinics are in urban settings and were built in response to the heroin epidemic of the 1970s. But these days, addiction is disproportionately suburban and rural, and people in those areas are unconvinced by studies showing that methadone clinics don’t bring an increase of crime. Opposition to new clinic sites makes it difficult to expand access through these highly regulated, highly effective programs, says Kletter.

Nationally, methadone programs are in shortest supply where they’re needed most. Wyoming, for example, has seen a fivefold increase in opioid deaths over the past decade yet still lacks a methadone clinic, and West Virginia, which has the nation’s highest death rate from drug overdoses, has had a statewide moratorium on new clinics for a decade.

Overall, the reluctance to allow methadone treatment could blunt the effectiveness of an influx of spending from Congress. As it stands, only one in five Americans dealing with opioid addiction receives any treatment, and that treatment comes mostly from outpatient settings and self-help groups, according to a 2015 study from Johns Hopkins Bloomberg School of Public Health in Baltimore.

“We need to change the conversation about opioid addiction, which is a chronic relapsing illness, just like diabetes,” says Brendan Saloner, an assistant professor at the Bloomberg School and the study’s lead author. Research studies have found that medication-assisted treatment can cut the mortality rate of addiction patients in half. And when nearly two million people addicted to opioids lack access to treatment, wider availability of helpful therapies—methadone included, despite its unpopularity—could help them get well again.