Cannabis and cognitive functions: A prospective study

Varma, Vijoy K.; Malhotra, Anil K.; Dang, Ravinder; Das, Karobi; Nehra, Ritu

doi:10.1016/0376-8716(88)90061-0

Cited by 71 publications

(28 citation statements)

References 8 publications

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“…Although slightly attenuated at 6-week retest, the cannabis-related deficit remained apparent. Similarly deficits among cannabis users were found on aspects of the Rey Auditory Verbal Learning Test (Solowij et al, 2002), verbal memory (Messinis et al, 2006), the retrieval of certain types of word stimuli (Block & Ghoneim, 1993), and visuo-spatial recall (Varma et al, 1988). More generally, performance on a range of cognitive tasks appeared to deteriorate with increasing years of heavy frequent cannabis use (Messinis et al, 2006).…”

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confidence: 82%

Real-world memory and executive processes in cannabis users and non-users

Fisk

Montgomery

2008

J Psychopharmacol

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Real-world memory and executive processes in cannabis users and non-users http://researchonline.ljmu.ac.uk/1101/ Article LJMU has developed LJMU Research Online for users to access the research output of the University more effectively. Copyright © and Moral Rights for the papers on this site are retained by the individual authors and/or other copyright owners. Users may download and/or print one copy of any article(s) in LJMU Research Online to facilitate their private study or for non-commercial research. You may not engage in further distribution of the material or use it for any profit-making activities or any commercial gain.The version presented here may differ from the published version or from the version of the record. Please see the repository URL above for details on accessing the published version and note that access may require a subscription.For more information please contact researchonline@ljmu.ac.uk http://researchonline.ljmu.ac.uk/ Citation (please note it is advisable to refer to the publisher's version if you intend to cite from this work) The relationships between executive processes, associative learning and different aspects of real world memory functioning were explored in a sample of cannabis users and nonusers. Measures of executive component processes, associative learning, everyday memory, prospective memory, and cognitive failures were administered. Relative to nonusers, cannabis users were found to be impaired in several aspects of real world memory functioning. No other group differences were apparent. The absence of cannabis related deficits in those executive component processes and aspects of learning that are believed to support real world memory processes is surprising given that cannabis related deficits were obtained in real world memory. The present results are discussed within the context of neuroimaging evidence which suggests that cannabis users may exhibit different patterns of neural activation when performing executive tasks while not always exhibiting deficits on these tasks.Keywords: Cannabis, executive processes, prospective memory, cognitive failures 3 The focus of the present paper is real world memory functioning in abstinent cannabis users. More specifically we intend to explore the basis of cannabis-related deficits in prospective memory, everyday memory, and cognitive failures, and the extent to which these impairments are underpinned by deficits in pre-frontal executive processes. Given that cannabis is clearly the most popular illicit drug in North America, Europe and in other parts of the world (Andersson et al, 2005) it is of considerable importance to investigate whether consumption of the drug is associated with cognitive deficits.Cannabis contains a number of chemical compounds collectively known as cannabinoids. The psychoactive properties of cannabis are mainly due to one of these cannabinoids, Δ 9 tetrahydrocannabinol, (THC). Animal studies have revealed that chronic administration of THC causes hippocampal damage and impairs maze learning in rats ...

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confidence: 82%

Real-world memory and executive processes in cannabis users and non-users

Fisk

Montgomery

2008

J Psychopharmacol

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“…In a meta-analysis examining 11 studies, Grant and colleagues (2003) found that chronic cannabis use was associated with persistent but subtle deficits in learning and memory, but not in other cognitive domains. Other studies have demonstrated persisting deficits in processing speed, attention, working memory, visuospatial skills, and executive functioning (Bolla et al, 2002;Croft et al, 2001;Ehrenreich et al, 1999;Lyons et al, 2004;Pope et al, 1997;Pope & Yurgelun-Todd, 1996;Solowij et al, 2002;Varma et al, 1988). However, some studies found no persisting cognitive deficits among adults with histories of heavy marijuana use (Carlin & Trupin, 1977;Pope et al, 2002;Schaeffer et al, 1981), and one study found that observed neurocognitive deficits normalized within a month of abstinence (Pope et al, 2001).…”

Section: Introductionmentioning

confidence: 99%

Neuropsychological functioning in adolescent marijuana users: Subtle deficits detectable after a month of abstinence

Medina

Hanson

Schweinsburg

et al. 2007

J. Inter. Neuropsych. Soc.

260

259

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In adults, studies examining the long-lasting cognitive effects of marijuana use demonstrate subtle deficits in attention, executive function, and memory. Because neuromaturation continues through adolescence, these results cannot necessarily generalize to adolescent marijuana users. The goal of this study was to examine neuropsychological functioning in abstinent marijuana using and demographically similar control adolescents. Data were collected from 65 adolescent marijuana users (n 5 31, 26% females) and controls (n 5 34, 26% females) 16-18 years of age. Extensive exclusionary criteria included independent psychiatric, medical, and neurologic disorders. Neuropsychological assessments were conducted after . 23 days of monitored abstinence. After controlling for lifetime alcohol use and depressive symptoms, adolescent marijuana users demonstrated slower psychomotor speed ( p , .05), and poorer complex attention ( p , .04), story memory ( p , .04), and planning and sequencing ability ( p , .001) compared with controls. Post hoc analysis revealed that the number of lifetime marijuana use episodes was associated with poorer cognitive function, even after controlling for lifetime alcohol use. The general pattern of results suggested that, even after a month of monitored abstinence, adolescent marijuana users demonstrate subtle neuropsychological deficits compared with nonusers. It is possible that frequent marijuana use during adolescence may negatively influence neuromaturation and cognitive development. (JINS, 2007, 13, 807-820.)

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“…Neuropsychological studies in adults have indicated that within a few days of abstinence, heavy users demonstrate impairments in learning and memory, attention, visuospatial skills, processing speed, and executive functioning (Varma et al, 1988;Pope and Yurgelun-Todd, 1996;Pope et al, 1997;Croft et al, 2001;Bolla et al, 2002;Solowij et al, 2002;Lyons et al, 2004).Event-related potential studies suggest slowed information processing and difficulty focusing attention (Solowij et al, 1991(Solowij et al, , 1995. Heavy marijuana users have demonstrated reduced cerebellar and frontal blood flow both at rest and during verbal learning and memory, while also showing poorer verbal learning abilities (Loeber and Yurgelun-Todd, 1999;Block et al, 2000;Lundqvist et al, 2001;Block et al, 2002).…”

Section: Introductionmentioning

confidence: 99%

Abstinent adolescent marijuana users show altered fMRI response during spatial working memory

Schweinsburg¹,

Nagel²,

Schweinsburg³

et al. 2008

Psychiatry Research: Neuroimaging

172

168

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Marijuana is the most widely used illicit substance among teenagers, yet little is known about the possible neural influence of heavy marijuana use during adolescence. We previously demonstrated an altered functional magnetic resonance imaging (fMRI) activity related to spatial working memory (SWM) among adolescents who were heavy users of after an average of 8 days of abstinence, but the persisting neural effects remain unclear. To characterize the potentially persisting neurocognitive effects of heavy marijuana use in adolescence, we examined fMRI response during SWM among abstinent marijuana-using teens. Participants were 15 MJ teens and 17 demographically similar nonusing controls, ages 16-18. Teens underwent biweekly urine toxicology screens to ensure abstinence for 28 days before fMRI acquisition. Groups performed similarly on the SWM task, but MJ teens demonstrated lower activity in right dorsolateral prefrontal and occipital cortices, yet significantly more activation in right posterior parietal cortex. MJ teens showed abnormalities in brain response during a SWM task compared with controls, even after 1 month of abstinence. The activation pattern among MJ teens may reflect different patterns of utilization of spatial rehearsal and attention strategies, and could indicate altered neurodevelopment or persisting abnormalities associated with heavy marijuana use in adolescence.

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Cannabis and cognitive functions: A prospective study

Cited by 71 publications

References 8 publications

Real-world memory and executive processes in cannabis users and non-users

Real-world memory and executive processes in cannabis users and non-users

Neuropsychological functioning in adolescent marijuana users: Subtle deficits detectable after a month of abstinence

Abstinent adolescent marijuana users show altered fMRI response during spatial working memory

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