T WENTY YEARS ago Lisbon’s Casal Ventoso neighbourhood was the biggest open-air drug market in Europe. But since 2001, when Portugal decriminalised most drug use, the number of addicts has plummeted, and these days one has to know where to find them. One recent evening, three outreach workers from CRESCER , a charity that helps drug users, trudged up a hillside carrying bags of clean syringes, saline solution and pastries. In a grove of cane plants, half-a-dozen people were smoking crack or injecting heroin. A gaunt man leant over a friend’s face, helping him plunge a needle into his neck.

Marta Correia, a psychologist at CRESCER , is friendly with many of Casal Ventoso’s drug users, but the thin fellow was unfamiliar. “Call me John Doe,” he joked, grinning. He had been shooting heroin for 25 years, since he was 15, he said. Ms Correia gave him a pastry and some syringes, accepting used ones in return. Other users got sheets of tinfoil for their pipes, and were encouraged to enter treatment.

At the height of the epidemic in the 1990s, authorities estimated that about 100,000 Portuguese, or 1% of the population, were heroin users. “It cut across all social classes. Nearly every family had someone,” says Dr João Goulão, head of SICAD , the agency that directs Portugal’s addiction programmes. That generated the political will to take the fight against drugs out of the justice ministry and give it to the health ministry. Under the law of 2001, illegal drugs remain illegal and dealers are prosecuted. But possession for personal use is an administrative offence, not a criminal one. Anyone caught with a 10-day supply or less is ordered to visit the local Commission for Dissuasion of Drug Addiction. Rehabilitation programmes and opiate substitutes, such as methadone, are available to all users who want to quit.

First, do no harm

Since then, the number of problem heroin users has fallen to about 33,000. The government can claim only partial credit; drug epidemics tend to fizzle. But decriminalisation and treatment helped cut Portugal’s overdose rate to one of the lowest in Europe. As for America, in 2016 it had 63,600 fatal overdoses. In Portugal there were 27.

Portugal’s policies are based on “harm reduction” approaches pioneered in countries such as Switzerland in the 1980s. The idea is to emphasise treatment and prevention more than punishment, says Brendan Hughes of the European Monitoring Centre for Drugs and Drug Addiction ( EMCDDA ). Most European countries now have some form of harm-reduction policy, though the east is more conservative.

Some countries take things further. Many have safe injection rooms, supervised by medical professionals who check the drugs for safety. In Germany, the Netherlands and Switzerland, addicts who repeatedly fail methadone programmes may even receive free, government-prescribed heroin. “Heroin-assisted treatment” has been shown to reduce crime and deaths. And it appears not to recruit new users: shooting up at a government facility under a nurse’s gaze is hardly glamorous.

But lately Europe is facing different drugs. Cocaine use is up; in Barcelona, residues in wastewater suggest it more than doubled between 2011 and 2018. Most overdose deaths in the Netherlands are caused not by opiates but by party drugs like amphetamines or synthetic cannabinoids, or by ecstasy, which can cause dehydration. The drug GHB raises your libido, but can knock you out; it accounted for two-thirds of Dutch drug-related emergencies in 2016.

For stimulants like these, notes the EMCDDA ’s Andrew Cunningham, “there are no substitute treatments like methadone”. The same goes for methamphetamines, rare in most of Europe but common in the Czech Republic and Slovakia. (They are still known there as “Pervitin”, a brand of amphetamines distributed to Nazi soldiers.) In the past few years Czech meth has spread across Germany, mainly in paste form. The more dangerous crystal variant has popped up as well, often sold at T -shirt stands along the German border.

Resistance to decriminalisation can come from many sides. Moralistic Sweden has tough laws against even small quantities of drugs. That is one reason, critics say, why its overdose death rate is the second-highest in Europe after Estonia’s: users are afraid to call for help. Poland has needle exchanges, but under its present conservative government, the number of syringes distributed mysteriously dropped by half in 2016. In Copenhagen last summer police repeatedly raided the anarchist community of Christiania, where cannabis dealing had long been unofficially tolerated.

Getting tough on cannabis seems strange at a time when countries and American states are legalising it. Harm reduction began with cannabis in the 1970s, when the Dutch government began tolerating retail reefer sales in designated “coffee shops”. But tellingly, it never decriminalised the business of supplying the coffee shops, so the wholesale trade stayed illegal. “It makes no sense at all,” says Peter Schouten, a Dutch lawyer who hopes to become one of the country’s first legitimate marijuana farmers when a pilot programme is launched next summer.