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Good news for pot smokers
Oct. 18, 2005
Special to World Science
An oft-mentioned danger of marijuana smoking—so widely believed, the smokers themselves
point it out all the time—is that it supposedly kills brain cells.
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Courtesy the National Drug Intelligence
Center, U.S.A.
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Yet a new study has found the opposite: that one of marijuana’s active ingredients actually helps produce new brain cells,
while apparently reducing anxiety.
It’s part of a double whammy of good news for pot lovers, as another study has found that marijuana smoke is less carcinogenic than cigarette smoke.
None of this establishes that pot smoking is safe. Some past studies have found it produces notable
memory
impairments, although there is debate over how long these last.
Nonetheless, the new findings contain “good news for the medical marijuana movement,” chirped a press release from the
Journal of Clinical Investigation, which is publishing the study on new brain cells.
“Most drugs of abuse decrease the generation of new neurons [cells] in the brain,”
the statement continued.
But the study by Xia Zhang and colleagues from University of Saskatchewan in Saskatoon, Canada, found that rats
getting regular doses of an artificial version of a potent marijuana ingredient grew new brain cells faster
than other rats.
The new cells grew in the hippocampus, a brain area associated with emotional
expression and some aspects of memory formation.
The rats also exhibited less anxiety- and depression- like behavior after a month of the treatment, the study found. The
findings are to appear in the journal’s November issue.
The second, separate study found marijuana smoke is less carcinogenic than tobacco smoke.
Robert J. Melamede of the University of Colorado in Colorado Springs found that “although cannabis smoke and tobacco smoke are chemically very similar, evidence suggests that their effects are very different,” said a statement from BioMed Central, publishers of the
Harm Reduction Journal. The findings appeared Monday in the journal.
“The pharmacological effects of tobacco and cannabis smoke differ in many ways, mainly because tobacco smoke contains nicotine while cannabis smoke contains tetrahydrocannabinol (THC). The cancer-promoting effects of smoke are increased by nicotine, while they are reduced by THC.”
“Tobacco and cannabis smoke contain the same carcinogenic compounds – and depending on which part of the plant is smoked, cannabis smoke can contain more of them – but, whereas nicotine activates these carcinogenic compounds, THC has been shown to inhibit them in mice cells. THC is very likely to have protective effects against the carcinogens present in smoke in humans too, but cannabis smoke remains nonetheless carcinogenic.”
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