Madrid Residents Consume More Cocaine Than People in Barcelona, a Study Has Found

People in Madrid consume more cocaine than residents of Barcelona, but almost three times less cannabis. These are the conclusions reached by Madrid Salud specialists after analysing the city’s wastewater. Madrid’s city council presented the results.

The study was based on samples collected from December 2023 to October 2025 at eight wastewater treatment plants in the city. In total, around 400 water samples were analysed, reflecting consumption of illicit substances across 21 districts of Madrid and several neighbouring municipalities.

The analysis found that cocaine levels in Madrid are about 369 milligrams per day per 1,000 residents—slightly higher than in Barcelona (349). However, Madrid’s figures are significantly lower than in some other European cities, such as Lisbon (625), Rome (478), Porto (415), and Milan (402). Cocaine consumption is higher than in Madrid in the following Spanish cities: Castellón (752), Lleida (623), Santiago de Compostela (609), and Tarragona (1482).

The situation is the opposite for cannabis. In Madrid's wastewater, 77.2 milligrams per day per 1,000 residents were detected—far less than in Barcelona (220.7), Lisbon (150.8), or Amsterdam (319).

Specialists also examined other substances—amphetamine, methamphetamine, MDMA, and ketamine. They concluded that in some cases, drug levels depend on the day of the week. For example, MDMA is consumed much more often on weekends. Cannabis use, meanwhile, remains stable throughout the week.

In addition to illicit drugs, Madrid Salud analysed medications that may be subject to misuse. Among those most frequently detected were ketamine and benzodiazepines—especially lorazepam and lormetazepam—which are among the most commonly prescribed anxiolytic and sedative medications in Spain.

Separately, it is noted that in 2025, the Madrid Salud Addiction Treatment Institute assisted 11,895 patients—7.6% more than the year before. Most often, people sought help due to alcohol (40%), cocaine (24%), and cannabis (15%).