In the United States, marijuana consumption is increasing, while perceived risks of using marijuana are decreasing. This is particularly among young people (Johnston et al., 2014), which suggests that prevalence of chronic and heavy use will increase over time. Scientific literature that should be available to inform public policy, especially harm reduction approaches, has not kept pace with social, political, and legal changes. Marijuana use has been associated with deficits in cognitive function, particularly memory (Solowij & Battisti, 2008). It has also been suggested that regular marijuana use decreases IQ (Meier et al., 2012). Brain-based mechanisms of chronic marijuana use remain poorly understood, and the literature lacks a clear foundation of basic associations between chronic marijuana use and global brain structure. The current proposal seeks to collect structural MRI and cognitive assessments within a mixed sample of older adult chronic marijuana users and age-matched non-users in order to report basic associations between chronic marijuana use and brain structure, as well as correlations between brain structure and cognitive function. It is hypothesized that chronic marijuana users will show global reduced gray and white matter volumes and reduced cortical thickness compared to non-users. It is also hypothesized that chronic marijuana users will show deficits in attention, memory, and processing speed compared to non-users, and that differences in brain structure will be moderately and significantly associated with cognitive function. Findings from the study will increase understanding of the possible risks associated with marijuana use and inform need for harm reduction policies.
It remains unknown how long-term marijuana use may impact brain structure. This preliminary study will explore differences in measures of brain structure and cognitive function between older adults who are chronic marijuana users or healthy non-users. Findings from the study will increase understanding of the possible risks associated with marijuana use and inform need for harm reduction policies.
| Karoly, Hollis C; Thayer, Rachel E; Hagerty, Sarah L et al. (2017) TLR4 Methylation Moderates the Relationship Between Alcohol Use Severity and Gray Matter Loss. J Stud Alcohol Drugs 78:696-705 |
| Thayer, Rachel E; YorkWilliams, Sophie; Karoly, Hollis C et al. (2017) Structural neuroimaging correlates of alcohol and cannabis use in adolescents and adults. Addiction 112:2144-2154 |
| Thayer, Rachel E; Hagerty, Sarah L; Sabbineni, Amithrupa et al. (2016) Negative and interactive effects of sex, aging, and alcohol abuse on gray matter morphometry. Hum Brain Mapp 37:2276-92 |
