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Endocannabinoids

What are endocannabinoids?

The endocannabinoid system is an endogenous biological system that regulates functions including cognition, sleep, energy metabolism, and inflammation. It modulates different neurotransmitter systems in the brain, including dopamine, glutamate, and GABA using two major lipid-based mediators, anandamide and arachidonoyl-sn-glycerol, that act through type one and type two cannabinoid receptors.

Exogenous cannabinoids, such as delta-9-tetrahydrocannabinol (THC), the main psychoactive components of cannabis, and cannabidiol (CBD), impact on the endocannabinoid system. While disturbance of the endocannabinoid system after cannabis consumption has been associated with increased risk of psychotic illness, CBD alone has shown anti-inflammatory and antipsychotic properties.

What is the evidence on endocannabinoids in schizophrenia?

Moderate to high quality evidence finds a large effect of higher concentrations of anandamide in the cerebrospinal fluid of patients, a medium-sized effect of higher concentrations of anandamide in the blood of patients, and a medium-sized effect of higher expression of type one cannabinoid receptors on peripheral immune cells of patients. There were insufficient usable data for a meta-analysis on type two cannabinoid receptors, and authors report mixed findings.

Increased severity of positive and negative symptoms was associated with decreased anandamide levels in cerebrospinal fluid and increased expression of type one and two cannabinoid receptors in peripheral blood mononuclear cells.

Poor cognitive performance was associated with decreased anandamide levels in serum and cerebrospinal fluid, increased expression of type one and two cannabinoid receptors in peripheral blood mononuclear cells, decreased expression of endocannabinoid system-synthesizing enzymes in peripheral blood mononuclear cells, and increased expression of endocannabinoid system-degrading enzymes in peripheral blood mononuclear cells.

October 2020

Last updated at: 4:32 am, 22nd October 2020
To view documentation related to this topic download the files below
Fact Sheet Technical Commentary

NeuRA Libraries

Title Colour Legend:
Green - Topic summary is available.
Orange - Topic summary is being compiled.
Red - Topic summary has no current systematic review available.