Although about 7 million people in the US population use marijuana at least weekly, there is a paucity of scientific data on persistent neurocognitive effects of marijuana use. OBJECTIVE: To determine if neurocognitive deficits persist in 28-day abstinent heavy marijuana users and if these deficits are dose-related to the number of marijuana joints smoked per week. METHODS: A battery of neurocognitive tests was given to 28-day abstinent heavy marijuana abusers. RESULTS: As joints smoked per week increased, performance decreased on tests measuring memory, executive functioning, psychomotor speed, and manual dexterity. When dividing the group into light, middle, and heavy user groups, the heavy group performed significantly below the light group on 5 of 35 measures and the size of the effect ranged from 3.00 to 4.20 SD units. Duration of use had little effect on neurocognitive performance. CONCLUSIONS: Very heavy use of marijuana is associated with persistent decrements in neurocognitive performance even after 28 days of abstinence. It is unclear if these decrements will resolve with continued abstinence or become progressively worse with continued heavy marijuana use.

Agency
National Institute of Health (NIH)
Institute
National Institute on Drug Abuse (NIDA)
Type
Intramural Research (Z01)
Project #
1Z01DA000388-08
Application #
6830611
Study Section
(CNRB)
Project Start
Project End
Budget Start
Budget End
Support Year
8
Fiscal Year
2003
Total Cost
Indirect Cost
Name
National Institute on Drug Abuse
Department
Type
DUNS #
City
State
Country
United States
Zip Code
Jayanthi, S; Buie, S; Moore, S et al. (2010) Heavy marijuana users show increased serum apolipoprotein C-III levels: evidence from proteomic analyses. Mol Psychiatry 15:101-12
Kalechstein, Ari D; De la Garza 2nd, Richard; Newton, Thomas F et al. (2009) Quantitative EEG abnormalities are associated with memory impairment in recently abstinent methamphetamine-dependent individuals. J Neuropsychiatry Clin Neurosci 21:254-8
Flanagan, Jonathan M; Gerber, Alexandra L; Cadet, Jean Lud et al. (2006) The fatty acid amide hydrolase 385 A/A (P129T) variant: haplotype analysis of an ancient missense mutation and validation of risk for drug addiction. Hum Genet 120:581-8
Cadet, Jean Lud; Bolla, Karen; Herning, Ronald I (2006) Neurological assessments of marijuana users. Methods Mol Med 123:255-68
Matochik, John A; Eldreth, Dana A; Cadet, Jean-Lud et al. (2005) Altered brain tissue composition in heavy marijuana users. Drug Alcohol Depend 77:23-30
Bolla, Karen I; Eldreth, Dana A; Matochik, John A et al. (2005) Neural substrates of faulty decision-making in abstinent marijuana users. Neuroimage 26:480-92
Herning, Ronald I; Better, Warren E; Tate, Kimberly et al. (2005) Cerebrovascular perfusion in marijuana users during a month of monitored abstinence. Neurology 64:488-93
Bolla, Karen; Ernst, Monique; Kiehl, Kent et al. (2004) Prefrontal cortical dysfunction in abstinent cocaine abusers. J Neuropsychiatry Clin Neurosci 16:456-64
Radzius, Aleksandras; Gallo, Joseph; Gorelick, David et al. (2004) Nicotine dependence criteria of the DIS and DSM-III-R: a factor analysis. Nicotine Tob Res 6:303-8
Bolla, K I; Eldreth, D A; London, E D et al. (2003) Orbitofrontal cortex dysfunction in abstinent cocaine abusers performing a decision-making task. Neuroimage 19:1085-94

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