This document discusses cannabis and related disorders. It begins by noting that cannabis is the most commonly used illicit drug globally, with about 147 million users. It then defines cannabis and its various types, describing the main psychoactive component THC. The document outlines the mechanism of action of THC, which involves binding to cannabinoid receptors in the brain and elsewhere. Finally, it discusses cannabis use disorder, intoxication, withdrawal and other cannabis-induced disorders based on DSM-V and ICD-10 criteria.

1. Cannabis and other related
disorders
Yolanda N. Khumalo
MBBS IV (University of Botswana)
29/08/19

2. Objectives:
• Appreciate the prevalence of cannabis use globally.
• Define cannabis and recognize the different types available.
• Describe the mechanism of action of cannabis.
• Diagnose cannabis and related disorders.

3. Introduction
• Cannabis (marijuana) is the most commonly used illicit drug globally.
• About 147 million people i.e. 2.5% of the world population use cannabis compared to
cocaine (0.2%), opiates (0.2%).
• The highest prevalence rates are among Western Central Africa, North America and
Oceania.
• Males tend to have higher cannabis dependence prevalence rates compared to females.
• Certain countries have fully legalized cannabis for recreational use e.g., Uruguay and
Canada.
• Locally, cannabis account for a significant proportion of psychiatric admissions,
especially among the youth.

4. About Cannabis
Definitions of commonly used street
terms:
Blunt – cannabis with tobacco
Joint- cannabis cigarette
Commonly used street names
• Weed
• Mary Jane
• Aunt Mary
• Grass
• Ganja
• Pot
Synonyms:
Dagga
Marijuana
Bhang

5. About Cannabis cont…
• The term ‘cannabis’ refers to a genus of flowering plants in the family: Cannabaceae.
• Cannabis plant contains more than 421 chemicals of which 61 are cannabinoids.
• The most psychoactive cannabinoid is called: delta-9-tetrahydrocannabinol (THC).
• THC found in the flowering heads (“buds”), less in leaves and stems.
Types:
1. C. sativa
2. C. indica
3. C. ruderallis - negligible amounts of psychoactive compounds
• C. sativa and C. indica are cultivated for recreational and medicinal use.
• C. ruderallis cultivated for seeds and fiber (hemp), not considered illegal.
Significant amount of psychoactive phytocannabinoids

6. Mechanism of Action of Cannabis
• Delta-9-tetrahydrocannabinol (THC), binds to and is a partial agonist at (2)
cannabinoid receptors:
 Cannabinoid 1 (CB1) receptor
 Cannabinoid 2 (CB2) receptor
• CB1 receptors distributed throughout brain and other body structures e.g.,
liver, adipose tissue and vascular endothelium.
• CB2 receptors are present on immune cells throughout body (incl. microglia,
spleen).

7. Mechanism of cannabis cont…
delta-9-tetrahydrocannabinol (THC)
+
CB1 receptors
(dopaminergic mesolimbic brain circuit)
Presynaptic dopamine release.
NB: Chronic regular (> weekly) use downregulates brain CB1 receptors;
abstinence results in upregulation within several days.

8. Routes of administration
• Smoking
• Inhalation
• Oral intake
• Intravenously – extremely rare
Rapidly absorbed

9. Metabolism and Excretion
• THC metabolism is primarily by hepatic P450 isozymes 3A4 and 2C9
• Excretion is largely through feces (65-80%) and urine (20- 35%). Tests on
these samples may be positive for several weeks after last intake.

10. Diagnosis of Cannabis- related disorders
DSM-V ICD 10
Cannabis use disorder Dependence syndrome
Cannabis intoxication Acute intoxication
Cannabis withdrawal Harmful use
Other cannabis- induced disorders Withdrawal state +/- delirium
Unspecified cannabis-related disorder Psychotic disorder
Amnesic syndrome
Residual and late- onset psychotic disorder

11. Cannabis Use Disorder (CUD)

12. Cannabis intoxication
• Refers to behavioral and psychological changes that occur with recent use of cannabis.
• Impaired motor coordination, euphoria, anxiety, sensation of slowed time, impaired
judgment and social withdrawal are some of the symptoms of cannabis intoxication.
• Physical signs include; conjunctival injection, dry mouth, tachycardia, postural HTN and
increased appetite.
Management:
• Usually self-limiting; treatment is symptomatic.
• Acute behavioral disturbance – benzodiazepines
• Perceptual disturbances– may use antipsychotics.

13. Cannabis withdrawal
• Characterized by; irritability, anger or aggression, nervousness/anxiety, sleep
disturbances, decreased appetite, restlessness, and depressed mood.
• Abdominal pains, tremors, fever and chills or headaches, may also be present.
Management:
• Supportive and symptomatic
• Can be managed with a regime of benzodiazepines e.g., diazepam

14. Other cannabis-induced disorders
• Cannabis- induced psychotic disorder
• Cannabis-induced anxiety
• Cannabis-induced sleep disorder
NB: These are diagnosed (instead of cannabis intoxication or withdrawal) if
symptoms are so severe as to warrant independent clinical attention.

15. References
• https://www.who.int/substance_abuse/facts/cannabis/en/
• https://www.uptodate.com/contents/cannabis-use-and-disorder-in-adults-pathogenesis-
pharmacology-and-routes-of-administration
• https://www.unodc.org/wdr2016/en/cannabis.html
• 1.The PONES. Correction: The Global Epidemiology and Contribution of Cannabis Use and
Dependence to the Global Burden of Disease: Results from the GBD 2010 Study. PLOS ONE.
2016;11(10):e0165221.
• Opondo P.R. An introduction to the practice of psychiatry in Botswana. Botswana: House of
Gendero; 2014. p. 90-91.
• Association A. Diagnostic and statistical manual of mental disorders: DSM-V. American
Psychiatric Pub. 2013..