Case study: Cannabis might dampen the pain, but amplify the psychosis!

In a recent study published in the journal Psychiatry Research Case Reports, researchers present the case of a 27-year-old African American woman with a history of schizoaffective disorder suffering from fibromyalgia, a neurological condition characterized by chronic pain. The woman reported self-medicating with potent, dispensary-procured cannabis in gradually increasing dosages to suppress her pain, but with the side effects of cognitive dysfunction, profound fatigue, sleep disorders, and drastic mood swings alongside suicidal tendencies.

Case study: A Cautious Reminder about the Potential Risk of Psychosis when Cannabis Is Used as a Treatment for Chronic Pain. Image Credit: Sasun Bughdaryan / ShutterstockCase study: A Cautious Reminder about the Potential Risk of Psychosis when Cannabis Is Used as a Treatment for Chronic Pain. Image Credit: Sasun Bughdaryan / Shutterstock

Encouragingly, dietary interventions aimed at lowering the patient's free glutamate intake were found to reduce her pain to the extent that she voluntarily quit cannabis use following only a month of the dietary intervention. This, in turn, was found to result in a reduction in the patient's psychiatric symptoms and substantial improvements in her quality of life, suggesting that cannabis may have exacerbated her preexisting psychosis.

This case study serves as a warning to cannabis consumers, especially those who are self-medicating despite a family or medical history of psychosis or similar mental health conditions, of our limited current information on the side effects of cannabis consumption and to clinicians of the dangers of cannabis use, especially potent cannabis sources or in high dosages.

Cannabis – boon or bane in the war against pain?

Fibromyalgia is a multi-symptom neurological condition characterized by widespread muscle and body pain, chronic fatigue, severe headaches, sleep disorders, gastrointestinal discomfort, and sporadic mood reversals, including depression, suicidal tendencies, and anxiety. Alongside depression and anxiety, recent research has linked excessive glutamatergic neurotransmission and antagonist of the N-methyl-D-aspartate glutamate receptor (NMDAR) with the manifestation and progressive escalation of fibromyalgia and its symptoms, respectively.

Unfortunately, despite studies elucidating the mechanisms underpinning fibromyalgia's association with glutamate dysregulation, there hitherto remain no pharmacological treatments for the condition. This prompts numerous pain patients worldwide to seek alternative painkillers, often resulting in their self-medication with cannabis and its derivatives. This, in turn, has made pain management the most cited reason for cannabis consumption, with more than 82.6% of California's cannabis users, 87% of those in Michigan, and 80% of the United Kingdom's (UK's) users reporting pain-dampening as their primary use for the drug.

Alarmingly, human association-based observational studies and animal psychosis model systems have revealed that high concentrations or amounts of the drug can result in the manifestation or amplification of psychosis, particularly in individuals with a medical or family history of neurological disorders such as schizophrenia.

"While some studies have suggested that medicinal cannabis has potential long-term pain-relieving and quality-of-life benefits, it is not yet clear which populations may be at risk for adverse side effects, making it more difficult for recommendations to be made about using cannabis as a treatment."

About the study

In the present study, researchers present and discuss the case of a 27-year-old African American woman suffering from fibromyalgia and comorbid schizoaffective disorder. Data collection was conducted via a questionnaire. It included a detailed symptom history, medical records of failed interventions, and the potency and frequency of the patient's current cannabis use. The dietary intervention comprised in-depth patient training on the fibromyalgia benefits of low glutamate diets, as well as the recommendations on food products that naturally contain high free glutamate content (soy sauce, parmesan cheese, and flavor-enhancing food additives) and should therefore be avoided. Physical activity and calorific interventions were not recommended despite the patient being slightly overweight at baseline assessment.

The intervention lasted one month, at the end of which a follow-up health assessment (weight) and questionnaire evaluation (for the number of fibromyalgia- or schizoaffective disorder-associated symptoms) was carried out.

Study findings

The patient reported 97% adherence to the recommended dietary intervention during the one-month-long study. The glutamate intervention was found to be highly effective at reducing the patient's pain quotient – the case reported significant reductions in the number of reported fibromyalgia- or schizoaffective disorder-associated symptoms (19 symptoms reported at baseline reduced to only five following the intervention), alongside substantial improvements to their mental health (anxiety and depression). Encouragingly, the intervention had such a profound effect on the patient's pain and mood that she voluntarily discontinued cannabis use following the intervention.

Notably, the discontinuation of cannabis further improved the patient's neurological conditions, resulting in reduced junk food cravings, substantial weight losses, and reductions in her anxiety and hallucinations (the latter of which decreased from extremely frequent to 'infrequent and minor'). This suggests that cannabis may be directly contributing to exacerbations of preexisting neurological and mental health diseases.


A growing body of literature elucidates the potential role of cannabis, a cocktail of numerous psychoactive compounds, in exacerbating mental health diseases. Specifically, cannabis has been found to have agonistic effects on 5-hydroxytryptamine receptors (5-HTRs), transient receptor potential channels of the vanillin subtype (TRPV), and G protein-coupled receptors (GPRs) while also interacting with NMDA receptors. These interactions have been shown to substantially decrease pain tolerance in murine Parkinson's disease (PD) models. Cannabis and its derivatives have further been implicated in glutamatergic synaptic signaling, indirectly contributing to increased glutamate uptake, thereby causing a snowball effect when used as a self-prescribed painkiller.

"Before adjusting my diet, my life revolved around how I felt both mentally and physically. I was unaware that the food I was consuming was contributing to my lack of focus, exacerbating my poor mental health, causing gastrointestinal disturbances, and fibromyalgia flares, among others… once I finally fully committed to the new regimen my symptoms dramatically improved. I found my sleep and concentration were better, my fibromyalgia became manageable, and I had more energy. Additionally, my depression/anxiety lessened to a point where I could function in my day-to-day life."

The present study serves as both a warning to patients currently consuming (or planning to consume) cannabis for pain relief and a reminder to medical practitioners of the limited scientific knowledge backing claims of the benefits of cannabis in chronic pain therapy.

"Cannabis appears to reduce glutamatergic neurotransmission, resulting in reduced excitotoxicity and pain occurrence; however, higher dosages and more frequent use can result in NMDA hypofunction, which can lead to psychosis and other psychiatric symptoms in susceptible individuals. Psychiatrists may be best suited to identify new onset psychiatric symptoms in chronic pain patients self-treating with cannabis."

Journal reference:

Article Revisions

  • May 7 2024 - Error in news title fixed: Caste study changed to Case study.
Hugo Francisco de Souza

Written by

Hugo Francisco de Souza

Hugo Francisco de Souza is a scientific writer based in Bangalore, Karnataka, India. His academic passions lie in biogeography, evolutionary biology, and herpetology. He is currently pursuing his Ph.D. from the Centre for Ecological Sciences, Indian Institute of Science, where he studies the origins, dispersal, and speciation of wetland-associated snakes. Hugo has received, amongst others, the DST-INSPIRE fellowship for his doctoral research and the Gold Medal from Pondicherry University for academic excellence during his Masters. His research has been published in high-impact peer-reviewed journals, including PLOS Neglected Tropical Diseases and Systematic Biology. When not working or writing, Hugo can be found consuming copious amounts of anime and manga, composing and making music with his bass guitar, shredding trails on his MTB, playing video games (he prefers the term ‘gaming’), or tinkering with all things tech.


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