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Cognitive outcomes associated with long-term, regular, recreational cannabis use in adults: A meta-analysis


Lovell, ME and Akhurst, J and Padgett, C and Garry, MI and Matthews, A, Cognitive outcomes associated with long-term, regular, recreational cannabis use in adults: A meta-analysis, Experimental and Clinical Psychopharmacology pp. 1-24. ISSN 1064-1297 (2019) [Refereed Article]

Copyright Statement

Copyright 2019 American Psychological Association

DOI: doi:10.1037/pha0000326


Despite research advances, it remains unclear if long-term, regular cannabis use harms cognition once intoxication has passed. Our meta-analysis aimed to investigate the association between cognitive functioning and long-term (mean ≥2 years), regular (mean ≥4 days/week), recreational cannabis use in adults during abstinence (mean ≥12 hr). We searched PubMed, PsycINFO, CINAHL, Scopus, and Dissertations and Theses International for English-language articles from the date each database began until May 22, 2019. We identified study inclusion by completing abstract and full text screening using predetermined criteria and Preferred Reporting Items for Systematic Review and Meta-Analysis guidelines. We classified cognitive performance into 6 cognitive domains (attention, executive function, learning and memory, decision making, information processing, and working memory), and included a global measure. Effect sizes were calculated for each domain using univariate meta-analyses. There were 30 studies with a total 849 participants who used cannabis (M = 30.7-years-old, SD = 5.5-years-old) and 764 control participants (M = 30.3-years-old, SD = 5.9-years-old). Cannabis was associated with significant but small-magnitude deficits in executive function, learning and memory, and global cognition, while decision making had moderate deficits. There were small-magnitude and nonsignificant group differences for information processing, working memory, and attention. Cannabis use duration, age of onset, and prolonged abstinence (≥25 days) did not influence outcomes, except group differences in executive function were nonsignificant in analyses of prolonged abstinence. Our results suggest that long-term, regular cannabis use is associated with small to moderate deficits in some cognitive domains. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

Item Details

Item Type:Refereed Article
Keywords:cannabis, cognition, residual effects, adult, meta-analysis
Research Division:Psychology
Research Group:Clinical and health psychology
Research Field:Health psychology
Objective Division:Health
Objective Group:Specific population health (excl. Indigenous health)
Objective Field:Specific population health (excl. Indigenous health) not elsewhere classified
UTAS Author:Lovell, ME (Dr Monica Mellefont)
UTAS Author:Akhurst, J (Ms Jane Akhurst)
UTAS Author:Padgett, C (Dr Christine Padgett)
UTAS Author:Garry, MI (Associate Professor Michael Garry)
UTAS Author:Matthews, A (Dr Allison Matthews)
ID Code:134811
Year Published:2019
Web of Science® Times Cited:29
Deposited By:Psychology
Deposited On:2019-09-05
Last Modified:2020-07-23

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