And how the endocannabinoid system plays a key role in this disorder
If you’ve been keeping up with the latest news in cannabis research, you may have come across some recent studies on cannabis and psychosis. These studies – published in the prestigious JAMA Psychiatry and Nature Neuroscience – have provided some surprising and interesting new information. The first study showed that cannabidiol, CBD, may actually “normalize” the brain of people at high risk of psychosis, and the second study revealed some of the genetic underpinnings of cannabis use.1,2
Findings from the latter study started to pull at the thread of the cannabis-psychosis paradox – namely, those that use cannabis are more likely to be later diagnosed with schizophrenia, rather than cannabis use causing schizophrenia.2 This is the first published data that got to the core of how cannabis could potentially help those with the disorder, yet researchers have been studying the endocannabinoid system (the body’s internal cannabis pathway) and schizophrenia for many years.3 So, the question remains – is there therapeutic potential for cannabis in schizophrenia?
Schizophrenia affects 1% of the US population.4 While the “positive” symptoms, such as hallucinations and delusions, are the most recognizable symptoms, those with schizophrenia also experience “negative” (depression and problems with social behavior) and cognitive (difficulty with memory and cognition) symptoms. The condition is often not diagnosed until later in the second decade in life; however, schizophrenia maystart to develop earlier in life.3 Therefore, some people with “prodromal” (or early) schizophrenia may self-medicate with cannabis to alleviate some of these symptoms.
Once believed to be a disease caused solely by dysfunction of the chemical messenger dopamine, researchers have now linked the disorder to many different chemicals and pathways in the brain.4And the endocannabinoid system is one of those affected. Studies have found that levels of cannabinoids and cannabinoid receptors are dysregulated in those with schizophrenia, and preclinical studies have demonstrated a benefit of CBD in animal models. 5,6In fact, there is some evidence that CBD, given earlier in life, can help prevent the development of some aspects.7
Studies involving schizophrenia have produced similar results. CBD treatment has been shown to alleviate some of the cognitive symptoms of schizophrenia, as well as aspects of psychosis.8A recently published small clinical trial found that CBD, used as an adjunctive treatment, improved cognitive symptoms. 9 As there are currently no approved therapies that address theses symptoms, those with schizophrenia may benefit from CBD to improve cognition. Additionally, larger trials are needed to substantiate this effect; but it’s certainly a promising avenue of research.
- Bhattacharyya, S., et al, “Effect of Cannabidiol on Medial Temporal, Midbrain, and Striatal Dysfunction in People at Clinical High Risk of Psychosis: A Randomized Clinical Trial”, JAMA Psychiatry, 2018, Epub.
- Pasman, J.A., et al., “GWAS of Lifetime Cannabis Use Reveals New Risk Loci, Genetic Overlap with Psychiatric Traits, and a Causal Influence of Schizophrenia”, Nature Neurosci, 2018, Volume 21.
- Bioque,M., et al., “Peripheral Endocannabinoid System Dysregulation in First-Episode Psychosis”, Neuropsychopharmacology. 2013, Volume 38.
- Patel, K.R., Cherian, J., Gohil, K., Atkinson, D. “Schizophrenia: Overview and Treatment Options”, P&T, 2014, Volume 39.
- Millera, B.J., Culpepper, N., Rapaport, M.H., Buckley, P., “Prenatal Inflammation and Neurodevelopment in Schizophrenia: A Review of Human Studies”, Progress in Neuro-Psychopharmacology and Biological Psychiatry, 2013, Volume 42.
- Gururajana, A., Taylor, D.A., Malone, D.T. “Effect of Cannabidiol In A MK-801-Rodent Model of Aspects of Schizophrenia”, Behavioural Brain Research, 2011, Volume 222.
- Peresab, F.F., et al. “Peripubertal Treatment with Cannabidiol Prevents the Emergence of Psychosis In An Animal Model of Schizophrenia”, Schizophrenia Research, 2016, Volume 172.
- Isegera, T.A., Bossong, M.G. “A Systematic Review of the Antipsychotic Properties of Cannabidiol in Humans”, Schizophrenia Research, 2015, Volume 162.
- McGuire, P., et al. “Cannabidiol (CBD) as an Adjunctive Therapy in Schizophrenia: A Multicenter Randomized Controlled Trial”, The American Journal of Psychiatry, 2017, Volume 166.