Although cannabis has got a bad rap when it comes to psychotic disorders such as schizophrenia, the latest research findings indicate that the plant has been largely misunderstood. Studies suggest CBD may actually offset the development of schizophrenia and curb the episodes of psychosis. Better yet, it appears that the other major cannabinoid, THC, may not necessarily trigger the condition — at least not as a direct cause.
Today we’ll focus on the potential CBD treatment for schizophrenia. We’ll cover the recent studies on this subject, explain the mechanism of action, and debunk a few myths about cannabis and mental health.
Using CBD for Schizophrenia: Does It Make Sense?
Cannabis is a complex plant with 115 identified cannabinoids. Depending on the chemotype, cannabis strains may be THC-dominant and CBD-dominant.
Marijuana is known for significant amounts of THC, while hemp boasts higher concentrations of CBD and only traces of the intoxicating cannabinoid.
There are also terpenes, which influence the effect profile of each strain.
The majority of CBD oils available for sale are made from hemp, so their effects revolve around the benefits of CBD supported by other compounds in the plan. A growing body of scientific evidence suggests CBD may relieve anxiety, inflammation and pain, sleep disturbances, and balance mood.
The FDA has recently approved the first cannabis plant-derived medication, Epidiolex. It contains pure CBD and is recommended for treatment-resistant seizures. However, doctors may prescribe Epidiolex off-label for other conditions, such as schizophrenia.
What to Know About CBD and Schizophrenia?
There is a clear link between cannabis use and psychosis, as noted by epidemiological studies. However, a higher risk of schizophrenia has been associated with strains that have high THC content, and studies have notoriously mentioned a dose-response relationship for the risk of schizophrenia in cannabis users. This isn’t the case for high-CBD strains.
THC produces acute psychotic-like symptoms in healthy individuals after a certain dosage threshold is breached — but CBD decreases the THC-induced psychosis and cognitive impairment.
Patients with schizophrenia suffer from cognitive deficits — they affect up to 85% of the sufferers, so the potential positive effects of CBD on cognition have critical importance.
Below we shed more light on how CBD may help with schizophrenia.
Antipsychotic Properties of CBD
A case study published by Zuardi and colleagues found that CBD may successfully treat schizophrenia. The authors tested a dose of CBD up to 1500 mg daily for 4 weeks, which improved the acute psychotic symptoms (1).
Findings from a 2006 study that analyzed the efficacy of CBD as monotherapy for treatment-resistant schizophrenia in three individuals show that only one patient responded positively to the treatment, but the dosage might’ve been inadequate (2). A later study on the benefits of CBD for schizophrenia tested flexible doses up to 400 mg daily on 6 patients with Parkinson’s disease, finding improvement of psychotic symptoms in all participants over the course of 4 weeks.
Since then, CBD has been investigated for its antipsychotic properties in three clinical studies with contradictory results.
For example, a 2012 double-blind randomized controlled trial on the therapeutic effects of CBD showed that the cannabinoid was as effective as amisulpride, a common antipsychotic drug, in treating the symptoms of schizophrenia. On top of that, CBD had fewer side effects; it caused no weight gain and resulted in less extrapyramidal symptoms (4).
CBD was also tested as an adjunctive medication in the treatment of acute psychosis in people with schizophrenia and non-affective psychotic disorders. After 6 weeks of taking 1000 mg of CBD daily, the CBD group showed greater improvement of positive psychotic symptoms compared to the placebo group. At the end of their therapy, more patients in the CBD group were evaluated as “improved” on the CGI-I scale compared with the controls. Patients who took CBD also showed trend-level improvements in their cognitive performance and motor speed (5).
A similar 2018 study investigated the therapeutic effects of 600 mg CBD daily — divided into two doses — in comparison with placebo in a 6-week double-blind placebo-controlled randomized clinical trial. However, the lower dose didn’t have a significant impact on the psychotic symptoms and cognitive performance of the participants compared to the placebo group (6).
How Does CBD Work for Schizophrenia?
Despite being supported by several epidemiological and clinical studies, the mechanism of action behind the antipsychotic properties of CBD remains unknown. Unlike other antipsychotics, CBD doesn’t directly affect dopaminergic neurons. It also doesn’t bind to cannabinoid receptors like THC.
However, CBD does indirectly increase the CSF levels of anandamide, one of the main endocannabinoids, by blocking its metabolizing enzyme, fatty acid amine hydrolase (FAAH). Interestingly, anandamide levels show a negative correlation with the severity of psychotic symptoms, whereas increased levels of anandamide have been found to improve them clinically after a CBD treatment.
This may hint to CBD as the potential mediator in the management of psychosis through the aforementioned boost of the endogenous levels of anandamide. However, further research is needed to confirm this theory.
Over the past few decades, medical researchers have been exploring the endocannabinoid system as the potential therapeutic target for mental disorders (7). The current pharmacological treatment for schizophrenia is only partially effective and doesn’t tackle the negative symptoms. This has led scientists to search for new pharmacological targets — and the findings from the ECS studies are very promising.
However, there’s a discrepancy in clinical results regarding CBD’s efficacy in treating schizophrenia and psychotic episodes. They could stem from different doses of CBD, stages of psychosis, and heterogeneity of the condition.
Risk and Side Effects: Can CBD Cause Psychosis?
There’s currently no evidence that CBD can cause psychosis. In order to do that, the cannabinoid would have to induce intoxication, elevating anxiety, and paranoia in the dose-response pattern. CBD has been repeatedly shown to reduce anxiety, help with the symptoms of PTSD, addiction, and improve people’s response to stress. CBD has a balancing effect on the nervous system, reducing the hyperactivity and increasing the hypoactivity of neurotransmitters when needed.
CBD is a safe substance. Studies have tested doses as high as 1,500 mg daily without dangerous side effects. That being said, there are a few mild reactions you may experience when you take too much CBD at a time:
- Changes in appetite
- Dry mouth
There’s also a risk of CBD-drug interactions, so make sure to consult your doctor prior to buying CBD oil if you want to avoid them.
The relationship between cannabis use and schizophrenia refers to how THC affects the brain.
But are you sure you have been taught the truth? Let’s take a brief look at the effects of THC on people predisposed to schizophrenia.
Does THC Cause Schizophrenia?
THC is an anti-inflammatory compound with antidepressant-like properties. In low and moderate doses, it also has a relaxing effect on top of inducing an altered state of mind, such as euphoric mood, giggles, and tranquility. However, doses of THC that score higher than your tolerance may aggravate anxiety and trigger bouts of paranoia, especially in those who are sensitive.
Studies conducted in the past have shown a correlation between cannabis use and a faster onset of schizophrenia in people with a family history of the condition. However, the conclusion might have been too hasty, as the latest research shows.
A study performed by Harvard University has analyzed all contributing factors besides cannabis use, pointing to the hereditary burden as the main trigger of schizophrenia in cannabis users. According to the research team, cannabis can only spur the onset of schizophrenia, but it’s not a trigger per se.
In other words, if a person is predestined to have schizophrenia, they will develop it sooner or later.
According to Dr. Musa Sami, a researcher and psychiatrist from King’s College in London increased cannabis use would need to positively correlate with the severity of psychosis, which hasn’t been proven by any study to this day.
Finally, Italian scientists from the University of Calgary have recently tested whether cannabis use will further harm the brain structure of rats that were prenatally exposed to an inflammatory agent that disrupts dopamine signaling and causes behavioral symptoms of schizophrenia. To their surprise, exposure to THC during adolescence seemed to protect the rats’ brains. The authors of the study hypothesized that THC’s anti-inflammatory effects were responsible for offsetting schizophrenia (8).
How Much CBD to Take for Schizophrenia?
The studies we’ve covered above have tested how pure CBD affects the mental health of the participants. However, most people use full-spectrum CBD products, where CBD is only one of over 400 compounds. These compounds influence the way CBD affects the body and brain, so doses may vary between people. Whole-plant extracts require a lower dose than CBD isolates, for which most studies have used a daily dose of 600 to 1,000 milligrams.
If you’re using a full-spectrum or broad-spectrum CBD oil, it’s best to start with a low dose, say, 15 mg once or twice a day with food. If you don’t feel a difference in your symptoms after one week, increase by 10–15 mg and reassess the effects. Once you’ve found your optimal dosage, you can stick to it — there’s no risk of increasing your tolerance to CBD over time.
Do Your Research Before Buying CBD for Schizophrenia
The CBD market is regulated due to the current classification of hemp-derived products. As health supplements, CBD extracts aren’t subject to any standardization when it comes to quality and labeling. Although the market has positively evolved over the years, there are still many fly-by-night vendors churning out poor quality products with less CBD than advertised. Some of them may contain more than 0.3% THC; others may be contaminated with pesticides, solvent residue, and other impurities.
For this reason, you should always check how the company grows, tests, and processes its CBD products.
The best source of CBD is organically grown hemp. Hemp plants are dynamic bio accumulators, so they easily absorb everything from the environment they grow in. Organic farming ensures that you only get the good substances in the source material.
Another important factor on your checklist should be the extraction method. Premium-quality CBD oils are extracted using pressurized CO2; this method produces pure extracts with consistent potency throughout the batches. It doesn’t use additional heat or solvents, so you’re getting a product with a complete cannabinoid profile.
Last but not least, look for certificates of analysis or COA. This shows that each batch is tested by a third-party laboratory. Independent laboratories analyze the potency of the product and look for common contaminants, such as heavy metals, pesticides, or solvent residue.
Summarizing the use of CBD for Schizophrenia
CBD can be used to manage schizophrenia thanks to its therapeutic effects on psychotic symptoms. It may also have a role in preventing or treating cannabis-induced psychosis in vulnerable individuals who consume high-THC strains.
High CBD content may positively affect our mental health — not only by curbing psychosis but also by reducing anxiety and improving the body’s response to stress. Studies investigating the efficacy of CBD in mental disorders have found that the cannabinoid has a calming effect on the nervous system but without the dangerous side effects of commonly prescribed antipsychotic medications.
Clinical trials on CBD and schizophrenia have brought mixed results, most likely due to the discrepancy in dosages. If you’re considering taking CBD oil to improve the symptoms of your condition, make sure to consult a holistic psychiatrist who will have a good understanding of CBD and cannabis in general. Doing so will help you determine the effective dosage and avoid negative CBD-drug interactions.
- Zuardi, A W et al. “Antipsychotic effect of cannabidiol.” The Journal of clinical psychiatry vol. 56,10 (1995): 485-6.
- Zuardi, Antonio Waldo et al. “Cannabidiol monotherapy for treatment-resistant schizophrenia.” Journal of psychopharmacology (Oxford, England) vol. 20,5 (2006): 683-6. doi:10.1177/0269881106060967
- Zuardi, Antonio Waldo et al. Op. Cit.
- Leweke, F M et al. “Cannabidiol enhances anandamide signaling and alleviates psychotic symptoms of schizophrenia.” Translational psychiatry vol. 2,3 e94. 20 Mar. 2012, doi:10.1038/tp.2012.15
- McGuire, Philip et al. “Cannabidiol (CBD) as an Adjunctive Therapy in Schizophrenia: A Multicenter Randomized Controlled Trial.” The American journal of psychiatry vol. 175,3 (2018): 225-231. doi:10.1176/appi.ajp.2017.17030325
- Boggs, Douglas L et al. “The effects of cannabidiol (CBD) on cognition and symptoms in outpatients with chronic schizophrenia a randomized placebo-controlled trial.” Psychopharmacology vol. 235,7 (2018): 1923-1932. doi:10.1007/s00213-018-4885-9
- Leweke, F Markus et al. “Role of the Endocannabinoid System in the Pathophysiology of Schizophrenia: Implications for Pharmacological Intervention.” CNS drugs vol. 32,7 (2018): 605-619. doi:10.1007/s40263-018-0539-z
- Lecca, Salvatore et al. “Δ9-Tetrahydrocannabinol During Adolescence Attenuates Disruption of Dopamine Function Induced in Rats by Maternal Immune Activation.” Frontiers in behavioral neuroscience vol. 13 202. 6 Sep. 2019, doi:10.3389/fnbeh.2019.00202