Cannabis use and its link to psychopathological and functional outcomes: Insights from self-reports and hair data

Background
Cannabis products differ hugely in their levels of cannabinoids and due to the illegality of cannabis in many countries, consumers have little or no way of knowing the composition of the products that they purchase on the black market (Potter et al., 2018).  Thus, self-reported measures of cannabis use may not suffice to estimate the body’s actual exposure to cannabinoids, notably to the psychoactive component delta-9-tetrahydrocannabinol, which is hypothesised to drive the adverse outcomes caused by cannabis use (Di Forti et al., 2014). Hair samples allow for a retrospective window into three months of the body’s exposure to a substance. While early studies utilising hair methods to quantify cannabinoids showed scepticism about its utility, analytical pipelines have improved in the past years, and can now reliably detect cannabinoids at least in daily to weekly users (Scholz et al., 2021; Steinhoff et al., 2023).
Methods
Hair samples were assayed using liquid chromatography-tandem mass spectrometry (LC-MS/MS). These analyses will investigate how cannabis use at age 20 predicts changes in functional outcomes and psychopathology (e.g., well-being, delinquency, as well as internalising and psychosis symptoms) at age 24, in a swiss community sample of 1127 participants. Importantly, we will investigate whether hair data of cannabis exposure provides stronger estimates of the associations between cannabis use and functional/psychopathological outcomes than self-report measures.
Conclusion
Thus, these findings will provide insights into the possible utility of hair data as an additional measure for investigations into outcomes associated with high cannabis use.