Meet our people

Matthijs  Blankers

Matthijs Blankers

Senior Wetenschappelijk Medewerker

PhD. Psychologist. Researcher with a strong focus on methods, statistics and data science. Expertise in digital health development, research and implementation for addictive behaviors. Published in top-rated international scientific journals.

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Esther  Croes

Esther Croes


PhD. Medical doctor and genetic and clinical epidemiologist. International project leader and co-worker in a wide range of projects. Main focus of her work is on the somatic consequences of substance use: tobacco control, drug-related emergencies and viral hepatitis.

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Daan van der Gouwe

Daan van der Gouwe

Drugs researcher

Drugs researcher who monitors the Dutch market in illicit drugs. He also monitors New Psychoactive Substances, has expertise in (international) policy evaluations and is involved in the CADAP program. He is one of the leading spokespersons for Trimbos when it comes to drug-related issues.

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John-Peter  Kools

John-Peter Kools

Senior Drug Policy Advisor

International expert on substance use, drug policy and harm reduction. Coordinator of drug policy activities in EU program to support and strengthen national drug policy in Central Asia. His expertise also covers the field of criminal justice, law enforcement and the penal system.

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Margriet van Laar

Margriet van Laar

Head Drug Monitoring & Policy/Reitox Focal Point

PhD. Psychopharmacologist. Coordinator of Trimbos’ drug research and Head of Dutch Reitox National Focal Point of EMCDDA. Research topics: drug market estimates, substance use in nightlife scene, health effects of cannabis, drug-related mortality, evaluation of policies and risk of illicit drugs.

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Sander  Rigter

Sander Rigter

Projectmedewerker A

Researcher at the Drugs Information and Monitoring System (DIMS). Expertise in analyzing drug samples, their effects and drug policy. He has a vast national and international network in this field. Sander also coordinates a yearly monitor of the content of cannabis sold in Dutch coffee shops.

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Ruben  Vrolijk

Ruben Vrolijk

Scientific Employee

Research associate at the Drug Information and Monitoring System (DIMS). He has a background in toxicology and focusses primarily on the development of new analytical techniques for drug analysis, like Fourier Transform Infrared Spectroscopy and the overall management and functioning of the DIMS.

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