The Legend: The active ingredient in marijuana, tetrahydrocannabinol, kills brain cells.
Status: False
Analysis:
As discussed earlier in this blog, this myth came from a poorly done piece of research in which brain changes were observed in Rhesus monkeys who had been exposed to high doses of marijuana smoke, (Heath et al, 1980).
Subsequent research done on animals and humans has found no evidence of physiological changes in brains exposed to daily marijuana smoke, and further, no evidence of mental decline or lowered IQ in these regular users, (Castle & Ames, 1997).
Heavy users report a pattern of short-term memory impairment that can persist for months into abstinence, but this does not appear to be caused by physical damage to the brain.
In order to kill brain cells you have to use legal drugs, such as alcohol.
