Cannabis is known to cause psychotic disorders, and the increasing use
of cannabis constitutes an important health problem. Growing evidence
that cannabis causes the development of psychosis has led to an increase
in the number of studies in this field. This review aims to clarify the
role of cannabis use in the development of psychosis, discuss the current
literature about the underlying neurobiological mechanisms. For this
purpose PubMed was searched for the keywords “cannabis use, psychosis,
schizophrenia, endocannabinoid system, pathophysiology, neurobiology”;
the articles published in the last 10 years were reviewed. Epidemiological
studies showed that cannabis use starting at an earlier age is associated
with an increased risk of psychosis, this risk is more pronounced in
people with genetic predisposition and increases with heavy and high
potency cannabis use. Studies showed that the endocannabinoid system,
which plays a role in nervous system development and functions as a
homeostatic regulator in physiological processes, is affected by cannabis
use during critical periods of development like adolescence; cannabis use
affects physiological processes such as synaptic pruning due to the effects
of this system on neurotransmitters like glutamate and dopamine leading
to long-term behavioral and psychological consequences. Additionally,
evidence that dysfunctions in the endocannabinoid system play a role
in the etiology of schizophrenia suggests that cannabis affects the disease
process by worsening existing dysfunctions in this system. Understanding
the relationship between cannabis use and the development of psychosis
and underlying neurobiological mechanisms will help to identify new
treatment targets, and develop appropriate preventive approaches.
Keywords: Cannabis Abuse, Psychotic Disorders, Schizophrenia,
Endocannabinoids, Neurobiology