Cortical Thickness and Neurocognition in Adolescent Marijuana and Alcohol Users Following 28 Days of Monitored Abstinence

Abstract

ABSTRACT. Objective: Adolescent marijuana use continues to increase in prevalence as harm perception declines. Better understanding of marijuana's impact on neurodevelopment is crucial. This prospective study aimed to investigate cortical thickness and neurocognitive performance before and after 28 days of monitored abstinence in adolescent marijuana and alcohol users. Method: Subjects (N = 54; >70% male) were adolescent marijuana users (ages 15-18 years) with regular alcohol use (MJ + ALC; n = 24) and non-using controls (CON; n = 30) who were compared before and after 4 weeks of sequential urine toxicology to confi rm abstinence. Participants underwent magnetic resonance imaging, neuropsychological assessment, and substance use assessment at both time points. Repeated-measures analysis of covariance was used to look at the main effects of group, time, and Group × Time interactions on cortical thickness and neurocognitive functioning. Bivariate correlations estimated associations between cortical thickness, substance use severity, and cognitive performance. Results: Marijuana users showed thicker cortices than controls in the left entorhinal cortex (ps < .03) before and after monitored abstinence, after adjusting for lifetime alcohol use. More lifetime marijuana use was linked to thinner cortices in temporal and frontal regions, whereas more lifetime alcohol use and heavy episodic drinking episodes was linked to thicker cortices in all four lobes (ps < .05). Age of onset of regular marijuana use was positively related to cortical thickness (ps < .03). Conclusions: Adolescent alcohol and marijuana use may be linked to altered longer-term neurodevelopmental trajectories and compromised neural health. Cortical thickness alterations and dose-dependent associations with thickness estimates were observed both before and after monitored abstinence and suggest neural differences continue to persist 28 days after cessation of marijuana use. Neural recovery may be identifi ed with longer follow-up periods; however, observed changes related to use severity could have implications for future psychosocial outcomes. (J. Stud. Alcohol Drugs, 75, 729-743, 2014)

Structural brain markers are differentially associated with neurocognitive profiles in socially marginalized people with multimorbid illness.

“…In young clinical samples, thicker cortices may reflect aberrant neurodevelopmental pruning processes (Jacobus, Squeglia, Sorg, Nguyen-Louie, & Tapert, 2014;Lacerda et al, 2007). Such an interpretation is consistent with our finding that there is a higher rate of schizophrenia diagnoses in younger individuals within this sample, as well as a higher proportion of individuals with a history of special education.…”

Go/No Go task performance predicts cortical thickness in the caudal inferior frontal gyrus in young adults with and without ADHD

“…Alcohol use was not a significant predictor of cIFG thickness, and the effect of cannabis use was only significant after global cortical thickness was added to the model as a covariate. Other studies of adolescent substance use have noted decreased cortical thickness to be associated with heavier cannabis use in areas surrounding the cIFG (e.g., caudal middle frontal gyrus, insula, paracentral lobule), but not specifically in the cIFG (Jacobus et al 2014; Lopez-Larson et al 2011). Given the fact that cannabis effects on the cIFG were not included in our primary hypotheses, and these effects are only observed in a model controlling for global thickness, Go/No Go performance, and ADHD status in the current study, this finding needs to be replicated in future studies.…”

Cannabinoids and Epilepsy

“…In high doses, paranoia and psychosis can occur [137,269]. Long-term use of recreational cannabis in adolescents is associated with addiction (9 % overall but 17 % among adolescents) and impaired cognitive and academic performance [270][271][272][273][274]. Additionally, cannabis treatment in animal and human studies altered brain development (especially with use in early childhood) and structure [272,[275][276][277], creating long-lasting functional and structural brain abnormalities [277][278][279].…”