Cannabis is the most widely used illegal drug in the world. “Magnitude of Substance Use in India 2019” survey found that 2.83% of Indians aged 10–75 years (or 31 million people) were current users of cannabis products. Common names for cannabis preparations in Indian society include  Charas (resin),  Ganja (flower) and Bhang (seeds and leaves).

Cannabis products are derived from the plant “Cannabis sativa”. The plant occurs in male and female forms. The female plant contains the highest concentrations of more than 60 cannabinoids. Delta-9-tetrahydrocannabinol (Δ9-THC) is the cannabinoid that is primarily responsible for the psychoactive effects of cannabis. In humans, Δ9-THC is rapidly converted into 11-hydroxy-Δ9-THC, the metabolite that is active in the central nervous system.

The cannabinoid receptor is found in highest concentrations in the basal ganglia, hippocampus, and cerebellum with lower concentrations in cerebral cortex. This receptor is not found in the brainstem, a fact consistent with cannabis’s minimal effects on respiratory and cardiac functions.

The cannabinoid receptors are involved in cognition, memory, reward, pain, perception and motor coordination.


(1) Marijuana (THC content typically 0.5–5 per cent) is prepared from the dried flowering tops and leaves of the plant.

(2) Hashish (THC content typically 2–20 per cent) consists of dried cannabis resin and compressed flowers.

Cannabis is usually smoked in a ‘joint’ like a tobacco cigarette or in a ‘water pipe’ often mixed with tobacco.

Acute psychological effects

Cannabis produces euphoria, relaxation, perceptual alterations, impaired short-term memory & attention and intensification of ordinary sensory experiences.

The most common unpleasant psychological effects are anxiety and panic reactions.

Chronic psychological effects:

Tolerance to cannabis develops over a period of time. Withdrawal symptoms like irritability, restlessness, insomnia, anorexia and mild nausea are seen when a person abruptly stops taking high doses of cannabis.

1. Cannabis psychosis:

High doses of THC have been reported to produce:

👉Visual and Auditory Hallucinations.

👉Delusional Ideas.

👉 Thought disorders.

2. Cannabis and schizophrenia:

Cannabis use can precipitate schizophrenia in persons who are vulnerable (because of personal or family history and genetic vulnerability).

3. Cognitive impairment:

Cannabis use acutely impairs cognitive functioning.

The long-term use of cannabis produces more subtle cognitive impairment in the higher cognitive functions of memory, attention and integration of complex information.

Longer the period of heavy cannabis use, more pronounced is the cognitive impairment.

4. Amotivational Syndrome:

Chronic heavy cannabis use impairs motivation and social performance.

Regular cannabis users can experience a loss of ambition and impaired school and occupational performance.

5. Cannabis Flashbacks:

Some people can experience symptoms of cannabis intoxication even if they haven’t used cannabis for many days.

Behavioural effects:

👉There is a strong association of heavy cannabis use with discontinuing studies at young age and job instability in adulthood.

👉Among those who start cannabis use in the early teens, there is a higher risk of progressing to heavy cannabis and other illicit drug use.

👉Cannabis use has adverse effects upon family formation & mental health. There is also risk of involvement in drug-related crimes.

👉 The risk of accidents is high, if an intoxicated person attempts to drive a vehicle.


Treatment of cannabis use rests on the same principles as treatment of other substances of abuse: Abstinence and Support.

👉Abstinence can be achieved through direct interventions such as hospitalization or through careful monitoring on an outpatient basis by the use of urine drug screens which can detect cannabis for up to 4 weeks after use.

👉Support can be achieved through the use of individual, family and group psychotherapies.

For some patients, an antianxiety drug may be useful for short-term relief of withdrawal symptoms. For other patients, cannabis use may be related to an underlying depressive disorder that may respond to specific antidepressant treatment.

School based drug education programmes produce small, statistically significant reductions in cannabis use.

If you have any questions or concerns, please write in the comment box…


  • New Oxford Textbook of Psychiatry(2nd edition).
  • Kaplan and Sadock’s Synopsis of Psychiatry: 11th Edition

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