Is cannabis neurotoxic for the healthy brain? A meta‐analytical review of structural brain alterations in non‐psychotic users

@article{Rocchetti2013IsCN,
  title={Is cannabis neurotoxic for the healthy brain? A meta‐analytical review of structural brain alterations in non‐psychotic users},
  author={Matteo Rocchetti and Alessandra Crescini and Stefan J. Borgwardt and Edgardo Caverzasi and Pierluigi Politi and Zerrin Atakan and Paolo Fusar-Poli},
  journal={Psychiatry and Clinical Neurosciences},
  year={2013},
  volume={67}
}
Despite growing research in the field of cannabis imaging, mostly in those with a psychotic illness, the possible neurotoxic effects of smoked cannabis on the healthy brain have yet to be fully understood. There appears to be a need to evaluate the existing imaging data on the neuroanatomical effects of cannabis use on non‐psychotic populations. 
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[Cannabis-induced cognitive and psychiatric disorders].
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TLDR
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TLDR
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References

SHOWING 1-10 OF 63 REFERENCES
Effects of Cannabis Use on Human Brain Structure in Psychosis: A Systematic Review Combining In Vivo Structural Neuroimaging and Post Mortem Studies
TLDR
Evidence is found for consistent brain structural abnormalities in cannabinoid 1 (CB1) receptor enhanced brain areas as the cingulate and prefrontal cortices and the cerebellum in psychosis patients and subjects at risk for psychosis.
Potential protective effects of cannabidiol on neuroanatomical alterations in cannabis users and psychosis: a critical review.
TLDR
Cannabidiol (CBD) was shown to prevent THC associated hippocampal volume loss in a small pilot study and is supported by several animal experiments supporting neuroprotective properties of CBD mainly via anti-oxidative effects, CB2 receptors or adenosine receptors.
Neuroanatomical maps of psychosis onset: voxel-wise meta-analysis of antipsychotic-naive VBM studies.
TLDR
Vulnerability to psychosis is associated with consistent GM decreases in prefrontal and temporolimbic areas and neuroanatomical alterations in temporal regions may underlie the clinical onset of psychotic symptoms.
Regional brain abnormalities associated with long-term heavy cannabis use.
TLDR
These findings indicate that heavy daily cannabis use across protracted periods exerts harmful effects on brain tissue and mental health.
Cannabis and anxiety: a critical review of the evidence
TLDR
The nature of the relationship between cannabis use and anxiety, as well as the possible clinical, diagnostic and causal implications, are reviewed.
Lack of hippocampal volume change in long-term heavy cannabis users.
TLDR
Investigating the effects of cannabis smoking on the morphology of the hippocampus in older, long-term cannabis users found no significant adjusted differences in volumes of gray matter, white matter, cerebrospinal fluid, or left and right hippocampus.
Neuroimaging in cannabis use: a systematic review of the literature
TLDR
Functional neuroimaging studies suggest a modulation of global and prefrontal metabolism both during the resting state and after the administration of THC/marijuana cigarettes.
Induction of psychosis by Δ9-tetrahydrocannabinol reflects modulation of prefrontal and striatal function during attentional salience processing.
CONTEXT The aberrant processing of salience is thought to be a fundamental factor underlying psychosis. Cannabis can induce acute psychotic symptoms, and its chronic use may increase the risk of
Long-term consequences of adolescent cannabis exposure on the development of cognition, brain structure and function: an overview of animal and human research.
TLDR
The effects of frequent cannabis use during adolescence could be different from and more serious than during adulthood, an issue increasingly recognized in the field of cannabis research.
...
...