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Chronic Cannabis Use May Produce Neurotoxic Effects (Interview with Murat Yücel, PhD)
Chronic Cannabis Use May Produce Neurotoxic Effects (Interview with Murat Yücel, PhD)

(June 2, 2008 - Insidermedicine) Heavy, long-term cannabis use may result in minor structural abnormalities in the brain as well as some subclinical effects on memory and mental health, according to research published in the Archives of General Psychiatry.

Here are some facts about cannabis:

•    An estimated 147 million people – about 2.5% of the world population – use cannabis.

•    In the past decade, cannabis abuse has grown more than opiate or cocaine abuse.

•    Chronic cannabis use has been linked with selective cognitive impairment, development of cannabis dependence syndrome, and several negative health effects on the trachea and lungs.

Researchers out of ORYGEN Research Centre, the University of Melbourne, and the University of Wollongong performed high-resolution MRI on the brains of 15 men who had smoked more than five joints a day for more than ten years as well as 16 men who had not used cannabis. They also compared the two groups with respect to verbal learning skill and the presence of subthreshold symptoms of psychotic disorders.

In the cannabis using group, the hippocampus was an average of 12% smaller and the amygdala an average of 7.1% smaller, by volume, compared with those who had not used cannabis. Cannabis users were also more likely to have subthreshold symptoms of psychosis and performed significantly more poorly on tests of verbal memory.

We had a chance to speak with Dr. Murat Yücel from the ORYGEN Research Centre and the Melbourne Neuropsychiatry Centre, who elaborated on the findings of this study.

Today's research challenges the belief that chronic cannabis use has no major neurotoxic effects. Extremely heavy, long-term use may affect brain structures and possibly have an impact on memory and mental health.

For Insidermedicine in Depth, I'm Dr. Susan Sharma.