The Effects of Cannabis on the Adolescent Brain and Epigenetic Ageing

点击翻译按钮获取中文摘要

Cannabis is used by approximately 200 million people worldwide. This number is set to increase further as cannabis becomes legally available in the USA, Canada and beyond. Notably, adolescents may have an increased likelihood to sample cannabis due to their increased risk-taking behaviour and peer-influence. However, the potential adverse impact of cannabis use on the developing brain and an individual's epigenetics remain poorly understood. This therefore poses a key public health concern for cannabis legalisation. Interestingly, research has shown that typical adolescent regional brain changes differ in magnitude between individuals, and so the brain is thought to be highly susceptible to environmental factors. Brain regions associated with adolescent neurodevelopment are also known to highly intercorrelate with white matter fibres and express an abundance of endocannabinoid receptors. As cannabis acts on these receptors, adolescence could mark a crucial developmental window of heightened vulnerability to cannabis. We hypothesise that cannabis could alter the trajectory of typical brain development and epigenetic ageing. To test this hypothesis, I will gain access to neuroimaging, cognitive and genetic data from a major MRC-funded project: "How does cannabis use affect teenagers' brains, cognitive functions and psychological wellbeing? (CannTeen)". The CannTeen study consists of four groups (adolescent cannabis users, adolescent controls, adult cannabis users, adult controls) who were followed up every three months for one year. With access to this data, I aim to examine the differences between all four groups, to study the effect of cannabis use and age group on:- Brain white matter microstructure (corpus callosum and forceps minor) using diffusion tensor imaging techniques to analyse the chronic effects of cannabis across the two collected time points (1 year apart. - Working Memory Function, using the spatial N-Back task results from fMRI data collected from the two MRI sessions one year apart to analyse both acute and chronic effects.- Epigenetic Ageing, using DNA methylation techniques to examine epigenetic clocks and how the epigenetic age differs from the chronological age of the participant.To gain insight into the subjective effect of cannabis on adolescent function, and juxtapose with the objective results listed above, I will also conduct qualitative interviews with adolescent cannabis users for a thematic analysis. I will probe participants to explore how they think that cannabis has affected their brain function and explore confounding variables such as socio-economic or friendship strains. Importantly, previous research suggests that peer-led campaigns are most effective for adolescent audiences. So, to ensure greatest research impact and encourage research engagement with young people, I will contact local schools and work collaboratively with teenage students to create a novel evidence-based drugs educational video resource to disseminate my findings on how cannabis effects the teenage brain. It will be shared on social media by our team including our young collaborators, to generate wide international reach and impact.The MRC, who has funded this project, aims to fund research at the forefront of science to improve human health. This project aligns well with this ethos as it is the first longitudinal study to directly compare how adolescent and adult brains and epigenetics differ in response to cannabis use. Through this project, I will generate world-first findings, with the potential to inform age-restriction sales policy. Plus, by engaging young people in this research, we aim to directly improve their informed decision-making when considering using cannabis. Therefore, we aim to improve public health from both angles.