A seven-year-long research project led by Spanish scientists has determined which drugs are preferred by specific countries, based on wastewater samples collected near the world’s largest cities. 

Similar wastewater studies this year showed that folks in Washington State consumed more cannabis than those in Amsterdam, and people in Vancouver took more opioids than their other Canadian neighbors. However, this latest study, published on Wednesday in the journal Addiction, compiled wastewater data from all over the world to compare drug levels among various nations. 

According to the report, this was the “largest wastewater‐based epidemiology study ever performed in terms of cities (120) and countries (37) involved and of the monitoring duration (2011–17).” 

“The team avoided collecting samples during public holidays, when higher-than-average drug use might skew the results,” wrote Becky Ferreira at VICE. The researchers also “tried to account for contamination of prescribed drugs that might leave the same chemical fingerprints as their illegal variants.”

The drugs of interest included methamphetamine, amphetamine, cocaine, and MDMA (a.k.a ecstasy or molly). Sadly, although the researchers looked for THC (weed) in the wastewater samples, they did not include it in their final analyses, likely because THC does not dissolve in water like the other drugs mentioned here. The study’s dates started in 2011 and ended in 2017. Below is what the researchers discovered. 

Gallery — Ecstasy Pills That Mimic Famous Brands and Logos:

Cocaine: Europe

Europe’s wastewater showed the highest levels of cocaine use, with far higher levels of the drug than even the South and Central American countries where coca is grown and processed into cocaine. 

Amphetamine: Europe

Europe also got top scores (do we even call them that?) for amphetamine use. Unlike in the US, Europe does not recognize certain forms of amphetamines as pharmaceutical medicines, such as dextroamphetamine, better known as Adderall. So, unlike wastewater studies for amphetamines in the US, all levels detected in Europe are from illicit use.

MDMA: The Netherlands

While the so-called “love drug” may be popular throughout Asia, North America, and Europe, one specific country in Europe rolled harder than anywhere else. In fact, three Dutch cities beat out the entire planet in regard to MDMA use: Eindhoven, Utrecht, and Amsterdam. This should come as no surprise, as the Netherlands, and Amsterdam in particular, is considered the world’s busiest hub for MDMA trafficking. 

Meth: North America and Australasia 

Oh, c’mon. You’re not really surprised by this, are you? The US, Canada, Australia, and New Zealand prefer tweeking on crystal meth over the feel-good vibes of MDMA and the rock-star status of cocaine. 

And while Europe’s overall meth usage was fairly low compared to the rest of the world, Eastern Europe showed relatively high levels of getting amped. Meth was most popular in Bratislava, Piestany, and Prague.

The World’s Most Drugged-Out Cities

The study also included “combined dose” data — where they basically added up the wastewater drug levels and compared them to a city’s population — to determine which cities consumed the most drugs overall. 

Those cities are Antwerp, Amsterdam, Zurich, London, Barcelona, and Athens — which, if you remember your high school geography, are all in Western Europe. Outside of Europe, the highest cities included Medellín, Colombia; Adelaide, Australia; and Seattle, Washington.

So, there you have it: Seattle is the most intoxicated city in the US — even more so than LA, New York, or Miami.

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