Cannabis Dopaminergic Effects Induce Hallucinations in a Patient with Parkinson’s Disease

Cannabis products that contain the tetrahydrocannabinol (THC) cannabinoid are emerging as promising therapeutic agents for the treatment of medical conditions such as chronic pain. THC elicits psychoactive effects through modulation of dopaminergic neurons, thereby altering levels of dopamine in the...

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Bibliographic Details
Main Authors: Katie Pizzolato, David Thacker, Nicole Del Toro-Pagán, Abeer Hanna, Jacques Turgeon, Adriana Matos, Nishita Amin, Veronique Michaud
Format: Article
Language:English
Published: MDPI AG 2021-10-01
Series:Medicina
Subjects:
Online Access:https://www.mdpi.com/1648-9144/57/10/1107
Description
Summary:Cannabis products that contain the tetrahydrocannabinol (THC) cannabinoid are emerging as promising therapeutic agents for the treatment of medical conditions such as chronic pain. THC elicits psychoactive effects through modulation of dopaminergic neurons, thereby altering levels of dopamine in the brain. This case report highlights the complexity associated with medicinal cannabis and the health risks associated with its use. A 57-year-old male with Parkinson’s disease was experiencing worsening tremors and vivid hallucinations despite therapy optimization attempts. It was discovered that the patient took cannabis for chronic back pain, and a pharmacogenomics (PGx) test indicated the presence of variants for the <i>COMT</i> and <i>HTR2A</i> genes. These variants could increase dopamine levels and predispose patients to visual hallucinations. Once the cannabis was discontinued, the patient’s hallucinations began to slowly dissipate. Cannabis use continues to expand as it gains more acceptance legally and medicinally, but cannabis can affect the response to drugs. This patient case suggests that cannabis use in combination with dopamine-promoting drugs, especially in a patient with genetic variants, can increase the risk for vivid hallucinations. These conditions support the importance of considering herb–drug interactions and PGx data when performing a medication safety review.
ISSN:1010-660X
1648-9144