France has one of the world’s highest levels of cannabis use, with around 40% of 17-year-olds reported to have used it in the previous year. While previous studies highlighted the existence of a possible causal relationship between initiation of cannabis use during adolescence and the subsequent level of educational attainment, researchers from Inserm and Sorbonne Université at the Pierre-Louis Institute of Epidemiology and Public Health have looked at the impact of this early experimentation on employment in adulthood. Their findings indicate that those having used cannabis are more likely to experience a period of unemployment later, especially if they were under 16 when they started. Their findings, based on the follow-up of 1,500 people over a nine-year period, have been published in Drug and Alcohol Dependence .
Among the 17.1 million young Europeans (aged 15 to 34) who declared having used cannabis in the previous year, 10 million were between the ages of 15 and 24 1 . Neuroscientific research data showing specific lesions in adolescent consumers support the idea that there is a direct negative effect of cannabis use on young people’s concentration, motivation and, ultimately, academic success.
Researchers from Inserm and Sorbonne Université looked at the age at which cannabis use began and its impact on the future professional integration of young people. Thanks to data collected from the Tempo 2 cohort, they have identified a link between early drug experimentation (before the age of 16) and difficulties in occupational integration in adulthood.
Their analysis focused more precisely on a sample of 1,487 young adults followed over a nine-year period between 2009 and 2018 3 . On four occasions during that period, the participants were asked how old they were when they first used cannabis and about their employment status. Other elements were also taken into account to avoid biasing the analysis, such as socioeconomic status, family situation, school difficulties encountered during childhood and adolescence, as well as the psychological assessment of the participants.
The findings suggest that those who declared having started their cannabis use at the age of 16 or younger are about twice as likely to experience a period of unemployment in adulthood 4 than those having never used cannabis.Whereas those who began their cannabis use after the age of 16 are 39% more likely to experience a period of unemployment in adulthood than those having never used the drug.
Early consumption: a risk marker for repeated episodes of unemploymentThe researchers also looked at the potential impact of early cannabis use on the risk of repeated episodes of unemployment. Those who began their cannabis use at an early age are three times more likely to experience several episodes of unemployment than those having never used cannabis.
According to the results of the study, those experimenting with cannabis at a later stage (over 16 years of age at first use) are 51% more likely to experience at least one period of unemployment compared with those having never used cannabis and twice as likely to experience repeated episodes of unemployment.
Furthermore, by comparing early and late cannabis users, the researchers found that the likelihood of experiencing repeated episodes of unemployment was 92% higher in the youngest consumer group than in those over 16 years of age at the time of initiation.
"These findings supplement the literature which shows that in addition to the frequency of cannabis use, the age at first use is associated with adverse consequences, not just on health but also on people’s social and economic lives. Cannabis use before the age of 16 can therefore be considered as a risk marker for unemployment. Delaying its use for as long as possible should be a public policy objective,” explains Maria Melchior, Inserm Research Director and last author of the study.
Based on the data collected from the Tempo cohort over a period of around 30 years, the researchers now wish to identify the factors that are predictive of cannabis use trajectories over time. An approach that is all the more important, given that those whose first use takes place during adolescence are increasingly likely to continue using in adulthood without the underlying mechanisms being well known.
1 European Monitoring Centre for Drugs and Drug Addiction (EMCDDA), 2017
2 The Tempo cohort is a long-term health research project set up by Inserm public health researchers
3 The participants were between 22 and 35 years-old at the time of their inclusion in 2009
4 Here this adult age corresponds to the 31-44 age group, the participants being between 22 and 35 years-old at the time of their inclusion in 2009