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LETTER OF THE DAY - Yes, ganja can damage the brain

Published:Saturday | March 8, 2014 | 12:00 AM


Marijuana is a gateway drug. Its use has side effects that affect the structure and function of the brain.

Yes, marijuana can damage the brain! Dr Daniel Amen has done SPECT brain scans on persons who have abused substances, including marijuana. In one study, he looked at a 57-year-old physician who had abused cannabis for 30 years. This doctor was unable to stop using it because of feelings of anger, irritability, agitation and anxiety when he tried to quit.

The first study was done when the doctor used marijuana heavily to the point of intoxication for three consecutive days. SPECT brain scans were done. The second study was done when the physician was off cannabis for one month and SPECT brain scans were done.

The study without marijuana showed decreased temporal lobe activity, likely from prolonged use of cannabis, but there was also patchy increased uptake, especially increased uptake in the deep left temporal lobe, often associated with anger, irritability and anxiety.


The study with heavy marijuana use showed overall marked decreased activity, especially in the prefrontal cortex and temporal lobes, associated with attention, memory and motivational problems. There was also a decrease in the overactive areas noted when the person was on marijuana compared to when the person was off marijuana. Dr Amen reported that the scan series may argue for the possibility of 'self-medication'; however, this 'medication' has the side effect of potential long-term damage of the brain.

Last month, I had an elderly female patient who drank ganja tea one morning, hoping that it would reduce her back pain from spinal stenosis. She had used about a centimetre of it to make the brew. When she came to see me, she exclaimed, "Doctor, I am dying, I feel like my brain does not belong to me." She had taken it because a neighbour suggested that she try it. I had to refer her to the emergency department of a nearby hospital for her to be stabilised.

Information for this letter was obtained from


Medical Doctor