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Adverse Structural and Functional Effects of Marijuana on the Brain: Evidence Reviewed

posted 01/11/2016

publication Pediatr Neurol 2016; -: 1-9 2016 Published by Elsevier Inc.

abstract
The growing use and legalization of cannabis are leading to increased exposures across all age groups, including in
adolescence. The touting of its medicinal values stems from anecdotal reports related to treatment of a broad range
of illnesses including epilepsy, multiple sclerosis, muscle spasms, arthritis, obesity, cancer, Alzheimer disease,
Parkinson disease, post-traumatic stress, inflammatory bowel disease, and anxiety. However, it is essential that
anecdotal data and the high level of interest in this treatment not obscure objective assessments of any potential
and realized short- and long-term adverse effects of cannabis, particularly with respect to age of onset and
chronicity of exposure. This critical review focuses on evidence-based research designed to assess both therapeutic
benefits and harmful effects of cannabis exposure and is combined with an illustration of the neuropathologic
findings in a fatal case of cannabis-induced psychosis. The literature and reported case provide strong evidence
that chronic cannabis abuse causes cognitive impairment and damages the brain, particularly white matter, where
cannabinoid 1 receptors abound. Contrary to popular perception, there are few objective data supporting preferential
use of cannabis over conventional therapy for restoration of central nervous system structure and function
in disease states such as multiple sclerosis, epilepsy, or schizophrenia. Additional research is needed to determine
if subsets of individuals with various neurological and psychiatric diseases derive therapeutic benefits from
cannabis.