Why has the frequency of cannabis induced psychosis increased?
March 22, 2024
(The cause of cannabis induced psychosis (CIP) and/or cannabis precipitation of schizophrenia is complicated. The following are comments from a lecture by Dr. Deepak Cyril D’Souza, Professor: Dept of Psychiatry: Director of Schizophrenia Neuropharmacology Research Group, Yale)
The relationship between cannabis and psychosis was described more than 200 years ago, yet science is still working to understand the relationship.
Background: Humans have an Endocannabinoid System that consists of CB1 receptors in the brain and CB2 receptors in the WBC, lymph, and periphery. Exogenous cannabinoids interact with our endocannabinoid receptors. The location of the CB1 receptors in the brain is consistent with the known effects of cannabis.
The increased frequency of cannabis induced psychosis (CIP) may be due to the change in composition of street cannabis. The cannabinoid, tetrahydrocannabinol (THC) is the psychoactive component of the plant. The cannabinoid, cannabidiol (CBD) may have antipsychotic properties. THC concentration has increased (up to 90% in some products), and CBD concentration has decreased in street cannabis. Increased frequency of CIP may be due to both the increased concentration of THC and decreased concentration of CBD. The more frequent the daily use and the higher the potency, the greater the risk of psychosis.
Synthetic cannabinoids (Spice, K2) are more potent than THC as they have much greater affinity for CB1. Furthermore, synthetic cannabinoids are full agonists at CB1 while THC is only a partial agonist at CB1.
Healthy individuals with schizophrenia (no cannabinoid exposure) have 15% fewer cannabinoid receptors in their brain than people without schizophrenia. Independent of cannabinoid exposure, schizophrenia may be a dysfunction of the endocannabinoid system. The role of cannabis in inducing schizophrenia is complicated and there is much to be learned. Cannabis can precipitate the presentation of schizophrenia in vulnerable individuals, but these individuals are difficult to identify. Family history of schizophrenia seems to be a high-risk factor.
For clarification, CIP is currently defined by symptoms such as hallucinations, illusions, delusions, paranoid ideas of reference, disorganized speech and behavior, and catatonia. It differs from the psychotic disorder which includes cognitive symptoms, functional deficits, mood symptoms and negative symptoms.
1) Acute psychosis occurs shortly after exposure and lasts hours.
2) Acute persistent psychosis occurs immediately after exposure and lasts days to weeks. May recur with cocaine exposure.
3) Chronic recurrent psychosis occurs days after exposure and intermittently recurs.
There is no specific treatment for CIP. Benzodiazepines and antipsychotic drugs are the mainstay of therapy.
Definitions:
cannabis - dried leaves, flowers, stems and seeds from Cannabis plant
cannabinoid - naturally occurring compounds found in Cannabis sativa plant such as delta-9 tetrahydrocannabinol (THC) the active component in marijuana and cannabidiol (CBD) which is 40% of plant resin. Cannabinoids exert their effect by interacting with specific cannabinoid receptors.
Endocannabinoid - naturally occurring substance in brain that binds to CB1 and CB2.
Pearl: When THC is exposed to air it oxidizes and forms cannabinol (CBN) which is less psychoactive than the THC. Cannabis exposed to air will have less potent effect when smoked due to increased CBN/THC ratio.
Question prepared by Donna Seger, MD
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