Schizophrenia is classified as a mental disorder that affects approximately 1% of the human population. Its onset is in late teens early 20’s but it can manifest in different stages of life. Males tend to get it earlier than females.

Symptoms: Thought disorder, Delusions, Hallucinations, Movement disorder Inappropriate affect, Deterioration of social behaviour, Impairments in working memory, attention and executive function.

This video of patients demonstrates some typical symptoms of this disease:


We don’t yet know what specifically causes schizophrenia and it is thought to be a cumulative effect of different genetic and environmental factors.

The genetic factor is thought to be an important one, as twin studies suggest a 50-80 % heritability, but so far only GWAS studies have only explained 5-7% of the variance due to genetic factors.

Genetic and environmental factors may play a role in the imbalance of brain neurotransmitters, such as dopamine and serotonin, that are believed to be the cause of the onset of this disease.

 Cannabis as a cause of schizophrenia

Cannabis consumption in the form of smoking has often been portrayed as a cause for schizophrenia, but there is no proven link and all the recent research suggests that there is no link in risk of schizophrenia and cannabis consumption.

The problem with recreational smoking is that the cannabis is often high in THC and has very little or none CBD. THC by itself has psychotropic effects that emphasize the symptoms of schizophrenia.

A controlled family study of cannabis users with and without psychosis

“The results of the current study suggest that having an increased familial morbid risk for schizophrenia may be the underlying basis for schizophrenia in cannabis users and not cannabis use by itself.”

Cannabis with high cannabidiol content is associated with fewer psychotic experiences

“…using high cannabidiol content cannabis was associated with significantly lower degrees of psychotic symptoms providing further support for the antipsychotic potential of cannabidiol.”



In recent years cannabidiol (CBD) has proven to be therapeutic option for this disease for its anti-psychotic effects and proven safety of use. Patients are recommended to use extracts with a high CBD:THC ratio, as THC with its  well known psychotropic effects, is not well tolerated for its side effects. At ratios over 7:1 the side effects of THC are negated by CBD. Extracts are preferred to pure CBD form, as the patient receives the “entourage effect” of all the other constituents found in this plant, mainly terperns and flavonoids.

There are also ongoing studies on the epigenetic role of CBD (as documented on skin cells) and the assumption is that CBD can modulate the expression of related genes and “silence” genes that may be the cause of schizophrenia. This is very exciting news as it could provide a treatment for the disease itself and not just the symptoms as it is treated presently.

THCV (Δ9-tetrahydrocannabivarin) is also a candidate for the treatment of symptoms of schizophrenia as it also has antipsychotic effects and clinical trials for PTSD patients are ongoing right now.



The phytocannabinoid, Δ9-tetrahydrocannabivarin, can act through 5-HT1A receptors to produce antipsychotic effects

We conclude that THCV has therapeutic potential for ameliorating some of the negative, cognitive and positive symptoms of schizophrenia.

Increasing endocannabinoid levels in the ventral pallidum restore aberrant dopamine neuron activity in the subchronic PCP rodent model of schizophrenia.

“…patients with schizophrenia demonstrate an inverse relationship between psychotic symptoms and levels of the endocannabinoid anandamide. In addition, increasing endocannabinoid levels (by blockade of enzymatic degradation) has been reported to attenuate social withdrawal in a preclinical model of schizophrenia.”
“we provide preclinical evidence that augmenting endogenous cannabinoids may be an effective therapy for schizophrenia, acting in part to restore ventral pallidal activity.”

Cannabidiol enhances anandamide signaling and alleviates psychotic symptoms of schizophrenia

“Our results provide evidence that the non-cannabimimetic constituent of marijuana, cannabidiol, exerts clinically relevant antipsychotic effects that are associated with marked tolerability and safety, when compared with current medications.”

Medical use of cannabis. Cannabidiol: a new light for schizophrenia?

“Behavioural and neurochemical models suggest that CBD has a pharmacological profile similar to that of atypical anti-psychotic drugs and a clinical trial reported that this cannabinoid is a well-tolerated alternative treatment for schizophrenia.”

A critical review of the antipsychotic effects of cannabidiol: 30 years of a translational investigation

“…CBD prevented human experimental psychosis and was effective in open case reports and clinical trials in patients with schizophrenia with a remarkable safety profile.”

“These results support the idea that CBD may be a future therapeutic option in psychosis, in general and in schizophrenia, in particular.”

Click to access psychiatry-2.pdf