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BRAIN - PHYSICAL EFFECTS and cannabis studies completed


Cannabis good for the brain? The endocannabinoid system regulates many body functions.

Some pharmaceutical psychoactive drugs are used to control symptoms in people defined by psychiatrists as depressed, schizophrenic, bipolar, or any of a huge and growing range of pseudo-mental disorders invented by a group of privileged people who vote to add conditions to the Diagnostic and Statistics Manual (DSM).

The methods by which these drugs work vary to some degree, but all of them operate by causing brain damage. It isn't surprising that many--perhaps most--people who take these drugs develop movement disorders sooner or later. Cannabis is different.

Science and Research

2012 - Study ~ Mitochondrial CB(1) receptors regulate neuronal energy metabolism.

2012 - Study ~ The cannabinoid CB1 receptor biphasically modulates motor activity and regulates dopamine and glutamate release region dependently.

2012 - Study ~ The Endocannabinoid System and the Brain.

2011 - Study ~ Effects of synthetic cannabinoids on electroencephalogram power spectra in rats.

2011 - News ~ Marijuana Compound Improves Brain And Liver Function In Animal Model Of Hepatic Encephalopathy.

2010 - Study ~ Alterations in the hippocampal endocannabinoid system in diet-induced obese mice.

2010 - Study ~ Disposition of Cannabichromene, Cannabidiol, and Δ9-Tetrahydrocannabinol and its Metabolites in Mouse Brain following Marijuana Inhalation Determined by High-Performance Liquid Chromatography-Tandem Mass Spectrometry.

2010 - Study ~ Quantification of brain endocannabinoid levels: methods, interpretations and pitfalls.

2009 - Study -  The influence of substance use on adolescent brain development.

2009 - Study - White Matter Integrity in Adolescents with Histories of Marijuana Use and Binge Drinking.

2009 - Study - Neuroimaging in cannabis use: a systematic review of the literature.

2009 - Study ~ Cannabinoid receptors in brain: pharmacogenetics, neuropharmacology, neurotoxicology, and potential therapeutic applications.

2008 - News ~ Astrocytes Implicated In Machinery Of Cannabinoid Signaling.

2008 - News ~ New brain cells implicated in machinery of cannabinoid signaling.

2007 - Study ~ The phytocannabinoid Δ9-tetrahydrocannabivarin modulates inhibitory neurotransmission in the cerebellum.

2006 - Study - A preliminary DTI study showing no brain structural change associated with adolescent cannabis use.

2006 - Study ~ Effects of Alcohol and Combined Marijuana and Alcohol Use During Adolescence on Hippocampal Volume and Asymmetry.

2005 - Study ~ Lack of hippocampal volume change in long-term heavy cannabis users.
2003 - Study ~ Cannabis and the brain.
1977 - Study ~ Absence of Cerebral Atrophy in Chronic Cannabis Users. Evaluation by Computerized Transaxial Tomography.
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The influence of substance use on adolescent brain development

Squeglia LM, Jacobus J, Tapert SF.

SDSU/UCSD Joint Doctoral Program in Clinical Psychology, San Diego, California, USA.


Adolescence is a unique period in neurodevelopment. Alcohol and marijuana use are common. Recent research has indicated that adolescent substance users show abnormalities on measures of brain functioning, which is linked to changes in neurocognition over time.

Abnormalities have been seen in brain structure volume, white matter quality, and activation to cognitive tasks, even in youth with as little as 1-2 years of heavy drinking and consumption levels of 20 drinks per month, especially if > 4-5 drinks are consumed on a single occasion.

Heavy marijuana users show some subtle anomalies too, but generally not the same degree of divergence from demographically similar non-using adolescents.

This article reviews the extant literature on neurocognition, brain structure, and brain function in adolescent substance users with an emphasis on the most commonly used substances, and in the context of ongoing neuromaturational processes. Methodological and treatment implications are provided.

PMID: 19278130 [PubMed - indexed for MEDLINE]PMCID: PMC2827693Free PMC Article

Images from this publication.See all images (2) Free text




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A preliminary DTI study showing no brain structural change associated with adolescent cannabis use

Lynn E DeLisi, Hilary C Bertisch, Kamila U Szulc, Magda Majcher, Kyle Brown, Arthika Bappal, and Babak A Ardekani
The Department of Psychiatry, New York University School of Medicine, New York, New York, USA
Corresponding author.
Lynn E DeLisi:; Hilary C Bertisch:; Kamila U Szulc:; Magda Majcher:; Kyle Brown:; Arthika Bappal:; Babak A Ardekani:
Received January 21, 2006; Accepted May 9, 2006.

White Matter Integrity in Adolescents with Histories of Marijuana Use and Binge Drinking

Jacobus J, McQueeny T, Bava S, Schweinsburg BC, Frank LR, Yang TT, Tapert SF

Neurotoxicol Teratol 2009 Nov-Dec; 31(6):349-55.

Structural brain abnormalities have been observed in adolescents with alcohol use disorders but less is known about neuropathological brain characteristics of teens with sub-diagnostic binge drinking or the common pattern of binge drinking combined with marijuana use.

 The goal of this study was to examine white matter integrity in adolescents with histories of binge drinking and marijuana use. Diffusion tensor imaging (DTI) was conducted with 42 adolescents (ages 16-19) classified as controls, binge drinkers, or binge drinkers who are also heavy marijuana users.

 Tract based spatial analysis identified shared fiber structure across individuals and facilitated voxelwise comparisons of fractional anisotropy (FA) and mean diffusivity (MD) between groups. Significant between group differences were found in FA in eight white matter regions (ps < or = .016) between the binge drink-only group and controls, including superior corona radiata, inferior longitudinal fasciculus, inferior fronto-occipital fasciculus, and superior longitudinal fasciculus.

Interestingly, in 4 of these same regions, binge drinkers who are also heavy marijuana users had higher FA than binge drinkers who did not use marijuana (ps<.05). MD did not differ between groups.

Findings are largely consistent with research suggesting less neuropathology in adolescents without histories of substance use. However, binge drinkers who also use marijuana did not show as consistent a divergence from non-users as did the binge drink-only group. Detection of white matter alterations may have implications in identifying early cognitive dysfunction in substance using adolescents.


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Neuroimaging in cannabis use: a systematic review of the literature

Martín-Santos R, Fagundo AB, Crippa JA, Atakan Z, Bhattacharyya S, Allen P, Fusar-Poli P,

Borgwardt S, Seal M, Busatto GF, McGuire P

 Psychol Med 2010 Mar; 40(3):383-98.

BACKGROUND: We conducted a systematic review to assess the evidence for specific effects of cannabis on brain structure and function. The review focuses on the cognitive changes associated with acute and chronic use of the drug.

METHOD: We reviewed literature reporting neuroimaging studies of chronic or acute cannabis use published up until January 2009. The search was conducted using Medline, EMBASE, LILACS and PsycLIT indexing services using the following key words: cannabis, marijuana, delta-9-tetrahydrocannabinol, THC, cannabidiol, CBD, neuroimaging, brain imaging, computerized tomography, CT, magnetic resonance, MRI, single photon emission tomography, SPECT, functional magnetic resonance, fMRI, positron emission tomography, PET, diffusion tensor MRI, DTI-MRI, MRS and spectroscopy.

RESULTS: Sixty-six studies were identified, of which 41 met the inclusion criteria. Thirty-three were functional (SPECT/PET/fMRI) and eight structural (volumetric/DTI) imaging studies. The high degree of heterogeneity across studies precluded a meta-analysis. The functional studies suggest that resting global and prefrontal blood flow are lower in cannabis users than in controls.

The results from the activation studies using a cognitive task are inconsistent because of the heterogeneity of the methods used. Studies of acute administration of THC or marijuana report increased resting activity and activation of the frontal and anterior cingulate cortex during cognitive tasks. Only three of the structural imaging studies found differences between users and controls.

CONCLUSIONS: Functional neuroimaging studies suggest a modulation of global and prefrontal metabolism both during the resting state and after the administration of THC/marijuana cigarettes. Minimal evidence of major effects of cannabis on brain structure has been reported.


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Effects of frequent marijuana use on brain tissue volume and composition

by Robert I. Block et al, NeuroReport, Vol. 11, Issue 3, pp 491-496 (abstract only)

RECEIVED: 10 November 1999

ACCEPTED: 3 December 1999

AUTHOR: Robert I. Block*, Daniel S. O'Leary~, James C. Ehrhardt±, Jean C. Augustinack§, M. M. Ghoneim, Stephan Arndt, James A. Hall~~

Full paper here, not on public access.


Department of Anesthesia, Westlawn Building, Room 5140, University of Iowa, Iowa City, IA 52242-1100, USA

Department of Psychiatry, University of Iowa, Iowa City, IA 52242-1100, USA; Department of Radiology, University of Iowa, Iowa City, IA 52242-1100, USA

Department of Anatomy and Cell Biology, University of Iowa, Iowa City, IA 52242-1100, USA

Department of Anesthesia, Westlawn Building, Room 5140, University of Iowa, Iowa City, IA 52242-1100, USA

Department of Psychiatry, University of Iowa, Iowa City, IA 52242-1100, USA

School of Social Work, University of Iowa, Iowa City, IA 52242-1100, USA

To investigate CNS effects of frequent marijuana use, brain tissue volume and composition were measured using magnetic resonance imaging (MRI) in 18 current, frequent, young adult marijuana users and 13 comparable, non-using controls.

Automated image analysis techniques were used to measure global and regional brain volumes, including, for most regions, separate measures of gray and white matter. The marijuana users showed no evidence of cerebral atrophy or global or regional changes in tissue volumes.

Volumes of ventricular CSF were not higher in marijuana users than controls, but were, in fact, lower. There were no clinically significant abnormalities in any subject's MRI. Sex differences were detected in several global volume measures. NeuroReport 11:491-496 © 2000 Lippincott Williams & Wilkins.


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