Alcohol was the most commonly cited primary drug (46.6%) followed by cannabis (14.5%), opiates (8.0%), amphetamines (7.6%) and cocaine (6.1%). It is striking to observe that when we look at the illegal drugs, cannabis selleck chemicals is first in line; almost twice as many treatment seekers claimed cannabis as their primary drug (14.5%) compared with any of the other illegal drugs. In European treatment demand figures, on the other hand, opiates are still first in line, but the number of primary cannabis users is steadily rising [1]. Of course, we have to take into account one of the main limitations of registration research: results are determined to a large extent by the number and types of treatment centres that have participated in the study, e.g. the proportion of inpatient versus outpatient centres [30].

Still, with this study we covered a very wide range of services, as a result of which our figures can be considered representative for the client population in this particular treatment system. Several hypotheses can be formulated regarding the rise of primary cannabis users seeking treatment, but thus far no study has been able to indicate which hypothesis is correct [1]. According to our opinion, several evolutions are interacting with each other. First, more people have started (regularly) using cannabis in the past years, resulting in more people – in absolute numbers – who experience difficulties or problems related to its use and eventually seek treatment. This tendency of increased use among the general population is not seen for other substances for the moment.

Second, several studies have examined the potency of cannabis and related changes over the years [30-32] and found that the potency of cannabis has systematically increased, also in the Netherlands, one of Belgium’s neighbouring countries. They suggested that this could have an effect on cannabis-related problems and treatment demand. Characteristics of primary cannabis users seeking treatment The objective of this article was to compare Anacetrapib treatment seekers with cannabis as primary drug with those with alcohol, opiates, amphetamines or cocaine as primary drug on a number of sociodemographic and treatment seeking variables. The sociodemographic profile of the former emerged as male, younger than 30 years old, Belgian and student. This profile is largely consistent with previous research, although the sex differences are more pronounced in our study [19]. We particularly want to focus attention on cannabis use among students in tertiary education. Several American studies have estimated last-year prevalence figures to be situated around 30% [34,35].