Effects of Marijuana Use on Brain Structure and Function

Brumback, Ty; Castro, Norma; Jacobus, Joanna; Tapert, Susan F.

doi:10.1016/bs.irn.2016.06.004

Cited by 26 publications

(9 citation statements)

References 124 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In response to interference compared to neutral trials, marijuana users had larger increases in activation in the right and left supramarginal gyrus, with the left cluster extending into the posterior MTG. These findings are consistent with prior studies on the effects of chronic marijuana use, which generally report alterations in frontal, parietal, and temporal regions during cognitive tasks (Batalla et al, 2013; Brumback et al, 2016; Martin-Santos et al, 2010). Such hyperactivity may serve as a mechanism to compensate for decreased efficiency and neural capacity due to marijuana use (Brumback et al, 2016).…”

Section: Discussionsupporting

confidence: 91%

“…These findings are consistent with prior studies on the effects of chronic marijuana use, which generally report alterations in frontal, parietal, and temporal regions during cognitive tasks (Batalla et al, 2013; Brumback et al, 2016; Martin-Santos et al, 2010). Such hyperactivity may serve as a mechanism to compensate for decreased efficiency and neural capacity due to marijuana use (Brumback et al, 2016). Compensatory theories posit that, in order to preserve cognitive function, additional regions that are not typically activated for a specific task must be engaged to maintain performance (Barulli and Stern, 2013).…”

Section: Discussionsupporting

confidence: 91%

“…Two systematic reviews reported that chronic marijuana use is associated with deficits across executive functions such as cognitive interference, problem solving, and decision making, though several studies have also reported null findings (Broyd et al, 2016; Crean et al, 2011). Neuroimaging studies suggest that marijuana users have altered activity in fronto-parietal regions when performing cognitively demanding tasks, which is generally expressed as hyperactivity despite comparable behavioral performance (Batalla et al, 2013; Brumback et al, 2016; Martin-Santos et al, 2010). However, studies using the Stroop paradigm, which requires conflict monitoring and inhibitory control, have yielded inconclusive results.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Synergistic effects of marijuana abuse and HIV infection on neural activation during a cognitive interference task

et al. 2018

View full text Add to dashboard Cite

Marijuana use, which is disproportionately prevalent among HIV-infected persons, can alter activity in fronto-parietal regions during cognitively demanding tasks. While HIV is also associated with altered neural activation, it is not known how marijuana may further affect brain function in this population. Our study examined the independent and additive effects of HIV infection and regular marijuana use on neural activation during a cognitive interference task. The sample included 93 adults who differed on marijuana and HIV statuses (20 MJ+/HIV+, 19 MJ+/HIV−, 29 MJ−/HIV+, 25 MJ−/HIV−). Participants completed a counting Stroop task during a functional magnetic resonance imaging scan. Main and interactive effects on neural activation during interference versus neutral blocks were examined using a mixed-effects analysis. The sample showed the expected Stroop effect for both speed and accuracy. There were main effects of MJ in the right and left inferior parietal lobules, with the left cluster extending into the posterior middle temporal gyrus, and a main effect of HIV in the dorsal anterior cingulate cortex. There was an interaction in the left fronto-insular cortex, such that the MJ+/HIV+ group had the largest increase in activation compared to other groups. Among MJ+, signal change in this cluster correlated positively with cumulative years of regular marijuana use. These results suggest that comorbid HIV and marijuana use is associated with complex neural alterations in multiple brain regions during cognitive interference. Follow-up research is needed to determine how marijuana-related characteristics may moderate HIV neurologic disease and impact real-world functioning.

show abstract

Section: Discussionsupporting

confidence: 91%

Section: Discussionsupporting

confidence: 91%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Synergistic effects of marijuana abuse and HIV infection on neural activation during a cognitive interference task

et al. 2018

View full text Add to dashboard Cite

show abstract

“…Previous work has reviewed both the cognitive [5,7,[51][52][53][54] and neurofunctional [55][56][57][58] effects of cannabis, both acutely and chronically, in the context of memory processing. Although a number of systematic reviews have summarised brain-structural alterations [56,59,60] as well brain-functional alterations [56,[59][60][61][62][63] more broadly over a wide range of cognitive domains associated with cannabis use, functional alterations in the context of memory processing in cannabis users have not been systematically and comprehensively summarized to include up-to-date literature [54]. Therefore, in order to summarise the current literature, we have conducted a systematic review of studies that have employed functional magnetic resonance (fMRI) techniques in conjunction with cognitive activation paradigms that involve memory processing, to investigate memory-related brain-functional alterations in long-term cannabis users (CU) compared to nonusers (NU).…”

Section: Introductionmentioning

confidence: 99%

A Systematic Review of Human Neuroimaging Evidence of Memory-Related Functional Alterations Associated with Cannabis Use Complemented with Preclinical and Human Evidence of Memory Performance Alterations

2020

View full text Add to dashboard Cite

Cannabis has been associated with deficits in memory performance. However, the neural correlates that may underpin impairments remain unclear. We carried out a systematic review of functional magnetic resonance imaging (fMRI) studies investigating brain functional alterations in cannabis users (CU) compared to nonusing controls while performing memory tasks, complemented with focused narrative reviews of relevant preclinical and human studies. Twelve studies employing fMRI were identified finding functional brain activation during memory tasks altered in CU. Memory performance studies showed CU performed worse particularly during verbal memory tasks. Longitudinal studies suggest that cannabis use may have a causal role in memory deficits. Preclinical studies have not provided conclusive evidence of memory deficits following cannabinoid exposure, although they have shown evidence of cannabinoid-induced structural and histological alteration. Memory performance deficits may be related to cannabis use, with lower performance possibly underpinned by altered functional activation. Memory impairments may be associated with the level of cannabis exposure and use of cannabis during developmentally sensitive periods, with possible improvement following cessation of cannabis use.

show abstract

“…In addition to changes on cognitive testing, studies employing brain imaging techniques have revealed structural changes associated with prolonged cannabis use and with initiation of use in youth. A recent review of this literature [117] demonstrated that consistent evidence exists for alterations in the medial temporal, frontal and cerebellar brain regions. Structural changes in both gray matter and white matter have been reported on functional MRI (fMRI) imaging.…”

Section: Cannabis Use In Youthmentioning

confidence: 99%

An overview of the adverse effects of cannabis use for Canadian physicians

Leduc‐Pessah

Jensen²,

Newell

2019

CIM

View full text Add to dashboard Cite

Purpose: Cannabis is the most widely used illicit substance and one of the most commonly used psychoactive substances in the world, preceded only by alcohol, tobacco and caffeine. Recent changes in legislation regarding cannabis use in Canada and potential upcoming changes worldwide may have a further impact on the prevalence of cannabis use. Thus, it is critical to understand the risks and potential adverse health effects of acute and long-term cannabis use. Current literature is lacking in many areas surrounding cannabis use, and for the most part is unable to provide clear associations once confounding variables are considered. Here we provide a general overview of the history of cannabis, the physical and mental health consequences, and the risks to specific groups. Source: A scoping search of published articles in PubMed from the start date (1946) until 2018. Principal finding: Current evidence supports an association between cannabis use and mild respiratory and cardiac effects, but no clear increased risk of cancer. Psychiatric disorders, including schizophrenia and anxiety, show associations with cannabis use; however, a causal effect of cannabis use is unclear. While no evidence for increased risk in pregnancy has been found, risk is still undetermined. Youth may be at a greater risk as earlier initiation of use increases the risk of adverse health effects. Conclusion: Overall, evidence for direct and long-term adverse effects of cannabis use is minimal and additional longitudinal studies will be required to better delineate unidentified effects.

show abstract

Effects of Marijuana Use on Brain Structure and Function

Cited by 26 publications

References 124 publications

Synergistic effects of marijuana abuse and HIV infection on neural activation during a cognitive interference task

Synergistic effects of marijuana abuse and HIV infection on neural activation during a cognitive interference task

A Systematic Review of Human Neuroimaging Evidence of Memory-Related Functional Alterations Associated with Cannabis Use Complemented with Preclinical and Human Evidence of Memory Performance Alterations

An overview of the adverse effects of cannabis use for Canadian physicians

Contact Info

Product

Resources

About