LISBON, Portugal — Tiago Praça donned his helmet with the Velvet Underground sticker, mounted his bike, and rode a few miles up to a white van sitting in a nondescript parking lot near a train bridge.

It was 11 a.m. A line was already forming.

Praça stepped to a window at the back of the van, grinned at the worker behind the glass, and accepted a small white cup of liquid methadone, the opioid-based addiction treatment medicine.

Like so many of his generation in Portugal, the middle-aged potter spent decades using heroin — and still struggles with an addiction to crack cocaine. But for years, he has biked to the van every day for the medicine he says has helped him regain a stable life.

“I come here, I go to work, I do pottery, I do my life,” he said one morning in February. “And then I come back here in the morning.”

Across Lisbon, health workers in such vans dispense the treatment every day, for free, to nearly 1,200 people. It’s part of what is perhaps the world’s most radical drug policy — one instituted amid a heroin crisis not unlike the one gripping Philadelphia and the United States.

After years of mounting overdoses, HIV infections and rampant heroin addiction, Portugal opted in 2001 for a daring experiment: The country decriminalized the use of all drugs.

It was an unprecedented move, and one that still garners worldwide attention, including from health-care professionals and government officials looking for answers to their hometown drug crises.

Portugal’s policy shift wasn’t instituted without controversy. In a deeply Catholic country of only 10 million — just a generation removed from the yoke of a repressive fascist government — stigma toward drug users runs high. Critics raised fears that the policy would increase addiction and turn the country into a haven for drug users.

But by the late 1990s, it seemed that nearly everyone in Portugal knew someone struggling with an addiction — much as the opioid crisis has pervaded the American consciousness. That made it easier to sell the reforms.

Decriminalization was accompanied by a comprehensive shift in perception: Drug use and addiction began being treated as public-health problems, not legal infractions.

Portugal stopped charging people caught with “a personal supply" of drugs. The country’s leaders also broadened treatment capacity and funded harm-reduction efforts such as needle exchanges to protect users from blood-borne diseases such as HIV.

A 2015 International Journal of Drug Policy paper looked at the “social costs” of drug use in Portugal before and after decriminalization — in other words, money spent on harm reduction and treating addiction and associated diseases such as HIV and hepatitis; costs to the legal system to prosecute drug users and dealers; and lost income and productivity due to overdoses or time spent in jail or treatment.

Researchers found that Portugal spent 9% more on treatment and other health-care interventions between 2000 and 2010 than it had in 1999. But costs related to lost productivity and legal proceedings decreased by around 25% — leading to an 18% drop in overall drug-associated costs.

Last fall, activists in Lisbon went further, launching a drop-in center to help users test narcotics for contaminants before using them. Lisbon’s government also opened its first supervised injection site — an initiative similar to the proposal that has roiled Philadelphia for years.

Portugal’s aim isn’t to force people with addiction into treatment but to help them stay alive until they are ready for it.

The result? Fatal overdoses have plummeted, from more than 350 a year in 2001 to about 50 a year now, one of the lowest rates in Europe. HIV infections resulting from injection drug use also have nearly vanished, dropping from 500 new cases in 2006 to 18 in 2017.

Portugal’s policies are not as unusual in the U.S. as one might think. Police-assisted diversion programs and initiatives that push treatment over prosecution already operate in cities such as Louisville, Ky., and Seattle. In Oregon, advocates are proposing a November ballot measure to decide whether the state should decriminalize possessing small amounts of illicit drugs. Philadelphia has allowed a small police-assisted diversion program in hard-hit neighborhoods.

But Philadelphia’s drug death toll remains staggering.

The city of 1.5 million has lost more than 1,000 people a year in each of the last three years — an annual rate of about 800 deaths per million people. In Portugal, the death rate is about 5 deaths per million people each year.

Philadelphia officials have begun to take a closer look at decriminalization. District Attorney Larry Krasner was among a group of U.S. prosecutors who visited Lisbon last summer. The city’s managing director, Brian Abernathy, has acknowledged that Portugal is one place the Kenney administration is looking for answers — although the coronavirus pandemic has put the city’s plans for a more robust diversion program on hold.

“We’re trying to meet people [in addiction] where they are and provide services, but at the same time we need to protect quality of life,” Abernathy said in March. “Some of what Portugal does helps find that balance."

Paulo Alexandre Lopes Louro took a seat in the waiting room of a nondescript office building in downtown Lisbon, down the street from the city zoo and a hospital.

Two days before this February meeting, police searching for witnesses to a robbery had caught him with a small supply of cocaine. They’d interviewed Louro, determined he hadn’t seen the robbery, and then gave him his drugs back — along with a summons to Lisbon’s “Dissuasion Commission.”

That’s the official title for what Americans would call a drug court, although this one has nothing to do with the criminal justice system. The Dissuasion Commission presides over cases concerning a personal supply of drugs, defined as enough for about 10 days.

Selling narcotics here remains illegal; police still pursue drug dealers. The morning before Louro arrived at the commission, Lisbon’s news programs were buzzing with details of a major trafficking bust.

At the commission, Louro met with a psychiatrist for about 45 minutes — an interview to learn about his drug use, and to determine whether he was in addiction, or just a casual drug user. Then he was ushered into a small conference room, where he took a seat across from Nuno Portugal Capaz, a trained sociologist who has run Lisbon’s Dissuasion Commission for years, and another staffer.

Capaz, dressed in jeans and a bright yellow, long-sleeved T-shirt, talked to Louro about his next steps.

About 80 percent of the 3,000 people who come before Lisbon’s Dissuasion Commission each year are recreational users and don’t face sanctions for a first offense. (During the coronavirus pandemic, the commission is operating over telephone and email.) Subsequent offenses might result in a fine, community service, or, in more severe cases, the loss of one’s driver’s license or other professional permits.

“Our mind-set is centered on the medical system. The justice system — in the end, their goal is not to increase the quality of life of a person.”

The goal is to get addicted people the help they need. The Dissuasion Commission offers free drug treatment, access to methadone, syringe exchanges, housing, counseling, and other services.

“Our mind-set is centered on the medical system,” Capaz said later. “The justice system — in the end, their goal is not to increase the quality of life of a person. The sanction of a criminal justice system will not make you stop [using drugs].”

Louro’s drug use had been deemed “problematic” — he was homeless, and had used heroin for years.

But Louro told Capaz he was doing better than he had been in a long time. He was living in a shelter, and on a waiting list for an inpatient treatment center. He was still using cocaine, but making regular visits to methadone vans and using far less heroin. Louro said he was ready to get his life together and reconnect with his family.

Capaz nodded, and asked Louro to sign paperwork agreeing to check in with the commission every three months. After nine months, as long he stayed in treatment, his case would be closed and he wouldn’t have to return to the commission.

The entire hearing took about 10 minutes.

“This is what we call an easy case,” Capaz said, pleased.

João Goulão was a young family doctor in the Algarve, Portugal’s southern region, home to stunning beaches and vistas and vacation spots, when the heroin crisis hit in the early 1980s.

The country had just shaken off a fascist dictatorship in the mid-1970s. The culture of excess, drug use and experimentation in the 1960s had mostly passed Portugal by.

The ensuing “curiosity that came with freedom,” as Goulão puts it, didn’t come with much knowledge about addiction. By the 1980s, the explosion of heroin use precipitated another crisis, as AIDS began to ravage the Portuguese who injected their drugs.

The epidemic hit hardest and first in the south, and Goulão’s practice soon became overwhelmed with patients struggling with addiction.

So Goulão became an addiction specialist less by choice than necessity. He tried harm-reduction tactics at his practice, but it was difficult.

Inpatient treatment was private, expensive, and ineffective. Access to methadone — the opioid-based medication that helps curb cravings and prevent overdoses — was rare and heavily restricted.

Goulão knew that methadone would allow drug users to avoid painful withdrawal, and that it and other opioid-based addiction treatments had been proven to help people achieve lasting recovery more reliably than quitting cold turkey and maintaining recovery solely through abstinence counseling.

But at the beginning of the crisis, the drug was available only in Porto, Portugal’s second-largest city, a few hours north of Lisbon. Goulão had to get special permission to treat his first methadone patient.

“I was astonished with the results,” he said. “It keeps people functional.”

In the late 1990s, the country’s new socialist government agreed to review and ultimately rewrite the country’s drug laws. They asked Goulão to join its task force.

The group proposed a strategy focused almost entirely on promoting public health: Decriminalize all drugs for personal use, institute nationwide harm-reduction programs, make methadone accessible, and expand effective inpatient treatment.

Portugal was already moving toward a decriminalization model: Despite draconian drug policies on the books in the early years of the crisis, policymakers and doctors such as Goulão had been quietly working to treat addiction as a health condition. And a 1993 law had already discouraged prosecuting personal drug possession and encouraged treatment for drug users with addiction, instead.

Other European countries held similarly liberal views on addiction. But Portugal was the first to stop charging anyone caught with a personal supply of narcotics. And it codified on a national scale the shifts in treatment and harm-reduction that doctors such as Goulão had been applying since the 1980s and 1990s.

After intense debate, Portugal’s parliament passed the laws — and then, a minor political miracle happened: A new conservative government whose members had opposed the laws was elected shortly after the drug laws changed, but its leaders still committed to implementing them, despite local and international pressure.

The policy still has its critics. Abstinence-focused organizations have argued that advocates overstate the benefits of decriminalization, and some politicians contend that the country needs to again consider punishing drug use. Last fall, Rui Moreira, the mayor of Porto, called for the prosecution of people who use drugs in public.

Decriminalization, he said at the time, “does not protect, purely and simply, the overwhelming majority of the population.” He added that he was “a little tired of hearing only about the dignity” of drug users.

“Decriminalization is important, because it introduces a lot of coherence in the system.”

Goulão, now the head of the national ministry that oversees the country’s anti-addiction initiatives, still keeps a photo of one of his early methadone patients in his office. A few years ago, the man, years into recovery, visited him to thank him.

Goulão acknowledged Portugal’s drug laws aren’t a panacea for addiction and drug use.

“But decriminalization is important, because it introduces a lot of coherence in the system. If you address the problem as a health condition, it makes little sense to criminalize this kind of behavior,” he said one afternoon in February, sitting in his office on the campus of Portugal’s health ministry in Lisbon, not far from the Dissuasion Commission. “You don’t criminalize a diabetic because he eats too much sugar, or a cigarette smoker. Even with what can be considered a self-inflicted disease, the state assumes the responsibility to contribute to a better life of its citizens.”

Although its efficacy as an addiction treatment has been widely recognized for decades, methadone is perhaps the most stigmatized of the drugs used for opioid use disorder in the United States.

The federal government allows it to be dispensed only through approved clinics that often have strict rules — miss a few doses, and you’re out. Drug users sometimes call such programs “liquid handcuffs.”

And then there’s the long-standing stigma that drug users shouldn’t lean on one drug to get off another. In Philadelphia, residents have battled against opening methadone clinics in their neighborhoods, arguing with no evidence that the sites increase crime and decrease property values.

Methadone vans like the kind that operate all over Lisbon do exist in the United States — including one outside the Atlantic County Jail in New Jersey — but the federal government has banned new ones from opening since 2007.

People involved in harm reduction and drug treatment in Lisbon say easy access to methadone — administered from the vans to about 1,200 people a day — is a key reason the city has so few fatal overdoses.

Every day, five methadone vans each visit three locations in the city, stopping twice a day at each. (The vans have continued to operate through the coronavirus pandemic, with slightly adjusted hours.) New participants must get a drug screening and a TB test before joining the roster.

Participants who miss several days in a row get a lower dose of methadone — because abstinence increases their overdose risk — before being restored to a typical dose.

Ares do Pinhal, the nongovernmental agency that operates the vans, began as an outreach project in the 1980s that handed out food and clothing to drug users. After decriminalization, the organization contracted with the government to launch the methadone program.

One recent morning, a van made its regular stop on the side of a highway near the former site of the Casal Ventoso neighborhood, where Ares do Pinhal first launched because it was the city’s most notorious drug zone. Despite once being razed, it still attracts a drug trade.

In a bright red sweatshirt, Bella Garcia, 34, bounded up to the van, hugged a familiar staffer and lined up for her dose, dispensed from a large bottle with a pump nozzle.

Garcia had been using heroin for 13 years, she said through a translator, ever since a boyfriend introduced her to it. She became addicted shortly after.

Through relapses and treatment and bouts of abstinence, she said, methadone has helped her stay alive.

Garcia comes to the van so as “not to be hungover when I wake up,” she said, referring to the intense pain of heroin withdrawal. “And I like the people who are here.”

Still, Garcia was frank about her plans for the day: She was going to buy heroin.

But using methadone means she doesn’t have to use as much heroin, helping protect her from overdose and withdrawal. After swallowing her dose, she grabbed another round of hugs, and left with a friend.

At the van’s final stop that morning, in a pristine neighborhood near a city hospital, Paul Mendes, 55, waited in line. Mendes said he had been going to the van for years, since, he said, he had been deported from the United States after 12 years in prison on drug-trafficking charges.

“If I was using in the States, I probably would be dead already.”

Born in Portugal but raised outside Boston, Mendes said he became addicted after his deportation. Methadone eventually helped him stabilize, and he worked in construction before retiring a few years ago because of other health concerns. He doesn’t drink or use any illicit drugs, he said.

Mendes’ Boston accent remains intact and he said he misses the country he still considers home. But he thinks often about what might have happened if he stayed.

“If I was using in the States,” he said, “I probably would be dead already.”

Lisbon still grapples with the fallout of its heroin crisis, but on a much smaller scale.

Every day, outreach workers from Crescer, one of Lisbon’s many addiction-focused nonprofits, load up their white van and drive to a gulch behind a housing project in the Picheleira neighborhood, about 20 minutes from downtown Lisbon. In the last month, to slow the spread of the coronavirus, many harm-reduction groups in Lisbon have pared back some office-based services, but kept up the most essential tasks — such as the gulch outreach.

Much like the notorious Gurney Street train encampment in Philadelphia’s Kensington, drug users there have cobbled together tents and huts made of scrap wood and tarps — protection from the elements, and from prying eyes.

Crescer staffers Ines Costa, a psychologist, and Ines Marinho, a nurse, have worked hard to build trust with the people who visit the gulch. One afternoon in February, Costa and Marinho navigated a worn path and met Antonio Morais at the door of a shack.

Morais, an artist and former heroin user, spends most of his day in the structure — about the size of a double-wide trailer — that he built four years ago from plywood and other spare materials. The shack is not Morais’ home. It’s a makeshift — and unauthorized — supervised-injection site.

Although Portugal legalized such sites during the 2001 reforms, the country didn’t open its first until last fall. After the change in the law, health officials had focused heavily on getting people drug treatment and establishing the Dissuasion Commissions.

Fatal overdoses are so low here that the overdose-reversing drug naloxone is not widespread. Still, drug-related deaths have ticked upward in recent years; authorities have attributed the spike to greater availability of drugs through the internet and traditional trafficking, and Goulão has stressed the need to update the country’s harm-reduction measures. About one person a week dies of an overdose in the entire country of Portugal, compared with three to four a day in Philadelphia.

This year, the Portuguese government began to distribute more naloxone to outreach workers.

But Morais and others had long worried about people in addiction who inject alone out of shame. Advocates described the opening of a supervised injection site as one of the few missing pieces in Portugal’s harm-reduction apparatus.

Morais skipped the official process and built his own to watch over his friends.

Costa and Marinho regularly give him dozens of kits — packed with clean needles, alcohol wipes, cookers, and other tools for safer drug use — to hand out to friends who won’t talk to an outreach worker. His site can hold about a dozen people at a time. Some even sleep there.

His work can be dangerous. On their latest visit to the gulch, Marinho helped Morais clean and bandage a stab wound on his hand he said he sustained when someone came by the site and tried to rob him.

Lisbon’s sanctioned supervised-injection site, also in a white van, sometimes parks on a hillside above the gulch. With two tables in the back, the specially equipped van parks for half the day in central Lisbon and, for the other half, on the ridge above the gulch. (This site, too, has stayed open during the pandemic.)

Even with Portugal’s seismic attitudinal shift toward drug use, its staffers were nervous about opening last fall.

“It’s a public health intervention. It’s like a doctor’s appointment.”

“We were very worried the national press would turn it into a negative thing,” said Adriana Curado, a psychologist with GAT, the harm-reduction organization that runs the mobile site. “But it ended up being a positive focus. This is important, because it’s a public health intervention. It’s like a doctor’s appointment.”

Staffers worked with neighbors who lived near the van’s planned stops and allowed them to tour it before opening.

Generally, Curado said, the public’s reaction in Lisbon was positive — unlike in Philadelphia, where neighborhood outrage in late February halted a planned supervised injection site in South Philly.

Only 116 clients have visited the van in Lisbon since last fall — the project was launched not because many people needed the service, but because it was one of the few harm-reduction efforts that hadn’t yet been tried here. One of the site’s first clients, who declined to give his name, said that when the site opened, he thought that people had finally started paying attention to drug users like him — deep in addiction, but with few options.

The man, in his early 40s, comes regularly to inject heroin inside the van, he said, and to get treatment for a leg wound. He was waiting to get into an inpatient treatment program, but had missed a few appointments, so the process was taking a while.

The supervised injection site, he said, was a way to keep safe while he waited.

How far Portugal has come, and perhaps how far it hopes to go, is evident in a dim, low-ceiling room on one of central Lisbon’s winding streets. There, Mariana Contla is trying to keep her peers safe.

Contla is a 20-something who runs the drug testing lab at Kosmicare, a nonprofit touted as one of Portugal’s newest harm-reduction measures. At first glance, the bright, homey storefront that sits below her lab could be easily mistaken for a coffee shop.

Instead, it’s a drop-in lab for young people who use drugs — largely recreational users who have no memories of their country’s heroin crisis.

The government-sanctioned operation, opened last fall, emerged from Portugal’s club and festival culture, where ecstasy and other club drugs are far more popular than heroin.

The concern for most recreational drug users in Portugal is less about deadly contaminants than it is about “spending money on something that’s not effective,” said Miguel, a professional who declined to give his full name for privacy reasons, and who said he regularly uses Kosmicare to test the ketamine and MDMA he buys for parties.

Clients bring drugs they’ve bought elsewhere for free testing two days a week, from 4 to 9 p.m.

“People who use drugs are trying to experience something positive,” said Kosmicare staffer Cristina Vale Pires. “We’re about harm reduction but also benefit maximization — because to have a nice experience is harm reduction.”

The clients and staff at Kosmicare have heard about the old days from parents scarred by the heroin epidemic. “My parents lost a lot of friends to heroin overdoses,” Contla said.

But Contla and her colleagues were raised to think of drugs without the stigma of earlier generations.

The message to Portuguese schoolchildren isn’t that drugs are bad — it’s that “drugs are so good they may become the center of your life,” says Goulão, the doctor who runs Portugal’s addiction response ministry. Prevention programs in schools focus on the potential consequences, good and bad, of drug use, and taking responsibility for one’s choices.

Many of Portugal’s efforts to help drug users aren’t radical on their own, health officials and advocates say. What’s radical is how they have brought so many tactics together so they can enhance each other for the greatest effect.

Most countries, including the United States, have been offering piecemeal versions of the same policies.

Philadelphia has operated a needle exchange since 1992 that serves tens of thousands of people annually. Police diversion programs for people caught using small amounts of drugs in public are common around the United States. Krasner’s office this year began dropping charges for people caught with a personal supply of drugs, as long as they can prove they’re in treatment.

Before the coronavirus pandemic, Abernathy, the city managing director, said he had spoken with Krasner and other officials about an “enhanced diversion model” similar to Portugal’s.

“Obviously the United States is not Portugal — there are going to be some differences,” Abernathy said in March. Namely, he said, Portugal has a universal healthcare system that made it easier to expand treatment — and a much less violent drug trade.

The pandemic, however, has “upended” plans to implement such a program, Abernathy said in a follow-up interview in April.

“Before COVID, we were intending to have a model where, essentially, a police-assisted diversion model expanded, where officers would interrupt bad behavior — open-air drug use, public urination, disrupting the peace in some way — and take that individual into custody, transport them to a centralized location, offer them services, and issue a citation,” said Abernathy.

Such a program isn’t practical right now, Abernathy said, because of the need for social distancing. Yet as criminal courts have closed because of the pandemic, police haven’t been arresting people for minor narcotics offenses; instead, they are issuing warrants for later court appearances.

But that’s not decriminalization, Abernathy is quick to say. “Police are still making arrests for drug dealing, still making arrests for other infractions — there’s an arrest warrant issued for a later date. They’re still held accountable for the crime,” he said. He said he was not sure whether those directives would remain in place after the pandemic had passed.

“We’re going to have to reboot and relook at everything we’ve done and what we’re planning to do — as it relates to this program specifically, and as it relates to pretty much every city operation,” Abernathy said.

But whatever changes Philadelphia makes with its laws, what’s different about Portugal is that it also has changed attitudes, and made recovery a national priority.

“Someone in power to coordinate the response — that’s what’s missing [in other countries].”

“Someone in power to coordinate the response — that’s what’s missing” in other countries, said Goulão, the national drug czar, who travels the world to speak about Portugal’s policies.

It’s impossible to completely replicate a Portuguese model abroad — the country’s policies were written with Portuguese health care, culture, and laws in mind. But studying an addiction crisis, developing a radical new approach to solve it, and actually seeing it through? That is possible with effort and political will, officials in Portugal say.

“You will never be able to do what we did,” said Capaz, the head of Lisbon’s dissuasion commission. “But you will be able to do things the way we did.”

Portuguese science writer Ana Gerschenfeld contributed reporting and translating for this article.