Cannabis shrinks brain volume: study
4th June 2008, 8:24 WST

Heavy marijuana use over many years appears to shrink parts of the brain that control emotion and memory, an Australian study shows.

Brain scans on 15 men who smoked at least five joints a day for more than a decade show for the first time that they have structural brain abnormalities not seen in non-smokers.

The researchers from the University of Melbourne say their findings should settle the historic controversy over the long-term effects of cannabis use with solid proof of the damage it causes.

"These findings challenge the widespread perception of cannabis as having limited or no consequences on the brain," said study leader Dr Murat Yucel, a clinical neuropsychologist at the Melbourne Neuropsychiatry Centre.

"Although modest use may not lead to significant neurotoxic effects, these results suggest that heavy daily use might indeed be toxic to human brain tissue."

The study, published in the US journal Archives of General Psychiatry, showed two important areas of the brain were smaller in long term smokers.

The hippocampus, thought to regulate emotion and memory, was 12 per cent smaller in volume and the amygdala, involved with fear and aggression, was reduced by seven per cent.

The smokers also were more likely to show mild signs of psychiatric disorders, but not enough to be formally diagnosed with one, Dr Yucel said.

The men also performed "significantly worse" in a memory test that involved trying to recall a list of 15 words.

He admitted the findings did not necessarily prove marijuana was responsible for the difference in brain volume but the findings strongly suggest this was the cause.

If this was the case, this indicated everyone was vulnerable to potential changes in the brain, some memory problems and psychiatric symptoms if they used heavily enough and for long enough, the researchers said.

The study involved men who were around the age of 40 and who had not taken other illicit drugs more than 10 times.

Another recent research review from the University of NSW showed that cannabis smokers had a 40 per cent increased risk of developing schizophrenia, and smoking daily drives the risk up two-fold. Other studies have linked the habit to gum disease and lung cancer.

Statistics show a third of Australians have smoked at least once in their life, with about 300,000 using daily.
AAP

Sweet, I can become a apathetic psycho with a poor memory and no control over my emotions.

It doesn't seem so bad.

5 joints a day. well i keep it to around 2 of high quality so am i good or what

That seems rather awesome. Shrinkage of those parts would probably result in an easier and more careless life.

Still not as harmful as alcohol. Think of someone who is drunk all day every day and compare to someone who is stoned all day every day.

Modern western culture is terrorized by the thought of death, and will do anything to distract itself from accepting that death is a part of life. Setting up safety nets to keep out anything that might possibly jeopardize our illusion of immortality is one of those things. Making sure everyone follows the same rules, keeps away from the same dangers, etc.

Freedom is an apparent sacrifice most people are apparently willing to make in order to maintain societies apparent sanity. In reality, its just a stupid game. Make your own rules.

And the relevance?

Don't listen to society/government and seek out and manifest your own goals and desires in life?

(relavance = every stoner (cannabis user) can relate)

5 joints a day for 10 years straight wowww

And how is that relevant to a study showing structural damage to the brain from toking? I think you missed my point.