How do we go about understanding drug use, both illicit and even licit? In France, the numerous epidemiological surveys conducted by the French Monitoring Centre for Drugs and Drug Addiction (OFDT) among the general population allow us to identify major addictive trends and fluctuations in the consumption of cannabis, cocaine, alcohol, and tobacco, and even gambling, which are well established among users in metropolitan France and its overseas territories. But to get to the heart of " weak signals ", the OFDT relies on investigators close to more closed circles and the most consumer populations: those of concerts, festivals, techno parties, chemsex or even populations in very high precarity.
By " weak signals To understand this, we must consider the quiet emergence of new synthetic drugs on the "supply market," substances not yet targeted by regulations, and the rise of new ways to consume substances already classified as illicit. Networks of informants, professionals, and the patient work of data collection underpin the OFDT's TREND and SINTES systems. colloquium organized to mark their 25th anniversary in the premises of the Directorate of Health on November 27th, was an opportunity to take stock of these health tools.
Created "in the context of the birth of addiction studies"
TREND and SINTES were founded in 1999, at a time when several major shifts were occurring in the field of drugs in France. New types of "consumers" were emerging, more socially integrated than the figure of the marginalized heroin addict. The products consumed were diversifying: the following appeared: MDMA-ecstasy, polydrug use involving mixing substances, drugs "sniffed" (taken nasally), the diffusion of amphetamines, of the ketamine, cocaine base (“ crack "). The 1990s were also a time of societal upheaval: Products and uses are becoming even more visible, better documented by social science research and institutional reports. In the context of the emergence of addiction studies and advances in neurobiology, the model of criminal punishment is crumbling; the problem lies less with the product itself than with the behavior of use. " explains Clément Gérôme, national coordinator of the TREND scheme, when he talks about the context of the birth of the two schemes.
TREND, SINTES, what are they?
TREND and SINTES were thus born at a time when attitudes towards drugs were changing: health authorities were seeking to limit risks for users. Their distinguishing feature is their ability to rapidly document the availability of new products, new psychoactive molecules regularly developed by clandestine chemists, novel uses little known to public authorities, and to identify the riskiest ones. This contrasts with large-scale surveys, which focus on uses deeply entrenched within broad population groups.
Devices without equal in the world
“ Abroad, knowledge of psychoactive substances in circulation relies on seizures carried out by police and customs services. " specifies Science and Future Sabrina Cherki, national coordinator of SINTES. The United States, Canada, and Australia have drug surveillance systems, but these are coordinated by law enforcement agencies or public health institutes. SINTES' unique methodology » is based on « anonymous and free collections, benefiting from highly resolution laboratory analyses Another distinctive feature is that SINTES produces its own data, unlike DIMS (Drug Information Monitoring System).) In the Netherlands, a "similar" system that works from " multiple data sources "For SINTES, more than 700 data collectors are involved in building this data.
Knowledge of the field, collection of qualitative data, and attention to the detection of emerging, so-called weak phenomena constitute a unique approach in Europe, and even in the world. Each time TREND gathers—in the manner of a sociological survey—the testimony of people in precarious situations for whom drug use becomes a survival strategy, this qualitative data allows for several things: contextualizing the conditions in which these drugs are consumed, identifying emerging phenomena early on, and identifying usage patterns linked to specific regions.
How do these tools work?
- They focus on populations with the highest risk of substance use, those not captured by general population epidemiological surveys: the techno party scene and urban marginality. Since the late 2000s, targeted surveys have steadily expanded their scope: the chemsex community, working-class neighborhoods, rural areas, small towns, and border regions. These surveys, though still relatively recent, are still sporadic. The first surveys focusing on seasonal and food processing workers in Brittany and the Provence-Alpes-Côte d'Azur region will be published in 2027.
- The information is produced by a network of people working in the health, social, community or law enforcement sectors, sufficiently involved in the field to capture and assess the latest trends in drug use.
- The information collected closest to the ground is inherently very different depending on the location within the country. These geographical specificities enhance the relevance of the information, an additional asset to help health authorities develop policies, which are referred to as "weak signals".
- Depending on the year, these "weak signals" represent up to 10 to 15 new synthetic psychotropic products offered by traffickers.
TREND: a look at non-normative » on drugs
TREND (for Recent Trends and New Drugs) monitors the recent emergence of new molecules and new uses through surveys of users. It also focuses on substances that affect only a small proportion of the population: cathinones, crack cocaine, LSD, ketamine, are concerned less than 20% of the population "Clément Gérôme points out. Their rarity means they appear very rarely in other major OFDT surveys: General population surveys lack the methodology and tools to quickly and accurately document emerging phenomena. "Information is gathered from populations that are difficult to reach because they are often on the move, in precarious economic situations, or completely excluded. TREND's approach to drugs is sociological," non-normative; drugs are neither beneficial nor harmful " explains Clément Gérôme. TREND surveys focus on the perceptions and feelings of the users themselves; they also describe their daily lives, their strategies for surviving and protecting themselves.
SINTES for circulating substances
The National System for the Identification of Toxic Substances (SINTES) is the other public health monitoring tool. It focuses on psychoactive substances in circulation: their composition, price, and methods of consumption. Here again, the cooperation of users in festive and precarious settings is crucial, thanks once more to the work of community and health professionals in the field. Samples are collected only in specific situations: users experience unexpected or undesirable side effects and agree to provide a portion of their dose for analysis, which is carried out by a network of toxicological laboratories linked to SINTES. The information is then sent to the national coordination center for the system. It is important to keep in mind that the number of samples collected remains insufficient to provide an accurate picture of the levels and compositions of products circulating nationwide.
The OFDT has the capacity to list indications of price each year of the main illicit drugs sold and specifies price fluctuations from one region to another.
An example of prices observed and summarized by TREND for the year 2024. Excerpt from Gérome C. (2025) Psychoactive substances, users and markets: trends in 2024, Trends, OFDT, November 2025, no. 170, 9p
Some examples of results
Access to alternative treatments for preventing opioid overdoses was justified by the analyses of the devices.
The investigations helped to identify the use of nitrous oxide among young users, or even the migration of drug traffickings on instant messaging platforms during the Covid-19 pandemic, a practice that has persisted ever since. Finally, a cluster of overdoses emerged in the Île-de-France region in May 2023. This event subsequently demonstrated the usefulness of the SINTES system, a key component of early health alert systems at both the national and European levels. The rapid identification of lethal doses of synthetic cannabinoids mixed with heroin made it possible to stop a cascade of accidents among users.
These measures do not yet cover the entire country.
The two systems do not exist equally across all overseas territories, with issues linked to those of neighboring foreign territories, or proximity to global drug trafficking hubs. SINTES is now present in Réunion, Martinique, Guadeloupe, French Guiana, Saint Martin, Saint Barthélemy and Mayotte, while TREND is only present in Réunion. Trend has plans to establish operations in overseas territories. " explain Clément Gérôme and Valérie Ulrich, head of the Focus scientific unit at the OFDT, to Science and FutureThey acknowledge that Historically, there has been a lack of information on addiction issues, but more generally, on public health data in these territories. SINTES is not only established in Corsica, but also in French Polynesia, comprising 3,500 km² of islands scattered across a territory almost as vast as Europe. "a territory with multiple insularities" Sabrina Cherki acknowledges which makes the transport of samples, logistical and analytical capacities complex, although the main reason remains health governance in this territory. "Due to a lack of resources, the collection points struggle to transport drug samples to the city where the local coordination is located."
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And what about the future?
Faced with the accelerating spread of new synthetic productsSINTES hopes to operate a " upgrade " explains its national coordinator, Sabrina Cherki. For "anticipate the arrival of new substances as much as possible ", the system envisions to purchase state-of-the-art equipment, to rely on certain bioinformatics tools (a so-called "molecular networks" approach, which facilitates the comparison of analyses when the chemical composition of a drug sample is unknown, editor's note). The future of both devices is linked, as with many public health issues, to... Additional means: extending collector networks in overseas departments and regions that have been little or not covered until now by the SINTES system, focusing more on other categories of consumers who do not frequent the areas that TREND is already investigating, rural areas, small towns.
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