Marijuana: Use and Abuse

Marijuana/dagga/dope/weed/pot/MJ, whether for therapeutic, medical or recreational use, is an illegal drug in South Africa, containing the psychoactive chemical Tetrahydrocannabinol (THC) which acts on the cannabinoid receptors of the brain.


How does marijuana work?:

When marijuana is smoked or ingested, THC is transported via the bloodstream to the brain. THC changes a person’s behaviour by binding, like a lock and key, to specific sites in the brain, called cannabinoid receptors. Most cannabinoid receptors are concentrated in areas of the brain associated with: thinking, memory, pleasure, co-ordination, concentration and sensory / time perception. THC acts on the body’s cannabinoid receptors which release dopamine, resulting in a feeling of euphoria or the “high” associated with the use of marijuana.

Can marijuana be abused?:

Yes, marijuana can be abused.

Substance or drug abuse is the habitual or routine use of a drug, e.g. marijuana, which results in the harming of the user. Using marijuana for non-therapeutic or non-medical effect is considered abuse.

Marijuana abuse is characterised by the use or consumption of marijuana in amounts or via methods which are harmful to the user. Marijuana is abused when it is:

  • smoked or ingested
  • taken for non-medical use but rather for the euphoric effect
  • taken in amounts that are harmful

Side effects of using marijuana:

Marijuana does not only affect the brain but also the heart, liver and lungs. Within minutes of inhaling marijuana smoke an individual’s:

  • heart rate can increase by 20 – 100%, thus increasing the risk of a heart attack.
  • the bronchial passages in the lungs relax and become enlarged, resulting in increased susceptibility to respiratory infections and lung diseases including cancer and emphysema.

Whether smoked or ingested marijuana use can result in:

  • weakened immune system
  • anxiety
  • panic attacks
  • paranoia
  • distorted perception
  • loss of co-ordination / motor control
  • short term memory loss
  • problems with learning
  • trouble with thinking and problem solving
  • increased risk of mental health issues and illnesses
  • acute psychosis

Exposure to marijuana has physical, biological, mental, behavioural and social consequences. The decision whether or not to use marijuana will always be a personal one. 

Please refer to the Policies page of this blog for BMH’s Student Policy on the Possession, Use and Distribution of Illicit Substances (including marijuana).

Adapted from:

How is Marijuana Abused; Smoking Marijuana and; How does Marijuana Work? –