Cannabis is the most commonly used illicit drug in Belgium; its use is concentrated among young adults aged 15-34 years and is more prevalent among males.
The health behaviour survey in school-aged children confirms that cannabis remains the main illicit substance used by Belgian teenagers; however, the prevalence and trends vary across the regions. Recent studies among 15- to 16-year-olds in school settings indicate that approximately one in six students in the Flemish Community and one in five students in the French Community have ever used cannabis. The studies among students in the Flemish cCmmunity indicate a slightly decreasing trend in cannabis use compared with the 2006 study, while in the French Community the trend remains stable.
The findings from studies in nightlife settings in both the Flemish and the French Communities found that cannabis is by far the most popular illicit drug, while MDMA/ecstasy has recently gained in popularity. Moreover, there are indications that use of new psychoactive substances (NPS) is becoming more established in nightlife settings.
A number of Belgian cities participate in the Europe-wide annual wastewater campaigns undertaken by the Sewage Analysis Core Group Europe (SCORE). This study provides data on drug use at a municipal level, based on the levels of illicit drugs and their metabolites found in wastewater. The 2017 data indicate an increase in the levels of MDMA between 2011 and 2016, with a subsequent decrease in 2017 in Brussels and Antwerp. The concentration of cocaine metabolites increased at the weekends in both cities.
The European School Survey Project on Alcohol and Other Drugs (ESPAD) was implemented in 2015 in the Flemish Community and the results indicate that levels of substance use among 15- to 16-year-old students are generally close to the ESPAD average, with the exceptions of cigarettes, inhalants and NPS. Only alcohol use in the last 30 days stands out as being higher than the overall average. However, the level of heavy episodic drinking during the last 30 days was the same as the ESPAD average. For other variables, the prevalence among the Flemish students was at the same level as or below the ESPAD average.
Studies reporting estimates of high-risk drug use and the numbers of people who inject drugs (PWID) can help to identify the extent of the more entrenched drug use problems, while data on first-time entrants to specialised drug treatment centres, when considered alongside other indicators, can inform an understanding of the nature of and trends in high-risk drug use.
In Belgium, the estimated number of PWID is derived using the human immunodeficiency virus (HIV) multiplier method. The available data suggest that that there have been no significant changes in the proportion of the population who have ever injected drugs over the last 10 years. Heroin remains the principal opioid used by PWID.
No population-wide estimate of high-risk opioid users is available for Belgium; nevertheless, data from specialised treatment centres indicate that heroin users constitute approximately one quarter of clients entering treatment, while use of heroin among first-time clients is lower. Cannabis was the most frequently reported primary substance for which clients entered treatment, and cannabis is also the most common primary drug among first-time treatment clients. Approximately one fifth of the clients in treatment are female; however, the proportion varies by type of substance used.