The Psychopharmacology of Cannabis and its Impact on Mental Health – A Primer
Cannabis (‘marijuana’, ‘hashish’) has been used for centuries for its medicinal and psychoactive properties and remains commonly used, worldwide.
It is a focus of particular current interest as many jurisdictions are making it available for medical use (‘medical marijuana’), decriminalising and even legalising it.
The cannabis plant has two main subspecies, Cannabis indica and Cannabis sativa, and they can be differentiated by their different physical characteristics.
Indica-dominant strains are short plants with broad, dark green leaves and have higher cannabidiol content than the Sativa plants in which THC content is higher.
The plant Cannabis sativa contains numerous different chemicals, including around 60 cannabinoids.
This review focuses on the compound with psychoactive properties – delta-9-tetrahydrocannabinol (THC). We cover CB1 and CB2 receptors and the harmful effects of cannabis on mental health. Medicinal cannabis will be covered in another article.
Zammit S et al., Self reported cannabis use as a risk factor for schizophrenia in Swedish conscripts of 1969: historical cohort study. BMJ. 2002.
Myran DTHarrison LD Pugliese M, et al. Transition to Schizophrenia Spectrum Disorder Following Emergency Department Visits Due to Substance Use With and Without Psychosis. JAMA Psychiatry. Published online September 27, 2023.