Published on August 28th, 2012 | by Steven Hodson0
Marijuana Smoking Teens Could Be Permanently Damaging Their Brains
The long term effects of smoking marijuana is just as contested as whether it should be legalized or not but a new study out of New Zealand may definitely add weight to the anti-legalize argument.
After following 1,037 New Zealanders from birth through to the age of 38 and monitoring their IQ and marijuana usage throughout the study found that smoking too much marijuana as a teenager could lead to significant cognitive decline, and that the damage could be permanent.
The IQ tests were first done at the age of 13, before any marijuana usage and then again at the age of 38, after a constant use of marijuana had developed. What they found was that the test subjects who were heavy marijuana smokers throughout their adolescence suffered an average drop of 8 points in their IQ scores.
Adolescent onset users, who diagnosed with cannabis dependence before age 18, tended to become more persistent users, but… after equating adolescent- and adult-onset cannabis users on total number of cannabis-dependence diagnoses, adolescent-onset users showed greater IQ decline than adult-onset cannabis users. In fact, adult-onset cannabis users did not appear to experience IQ decline as a function of persistent cannabis use.
The researchers are very quick to point out however that early onset marijuana usage causes cognitive decline. As one researcher said : “our data cannot deﬁnitively attest to whether this association is causal,” nor can it “reveal the
mechanism underlying the association between persistent cannabis dependence and neuropsychological decline.”
Of the argument can be made that as with all things moderation is the key but equally so the discussion around “when” and “what age” is just as important with researchers pointing out that the cognitive impairment found in adolescent smokers was not found in those who started smoking later in their life.
This suggests that marijuana could potentially have a neurotoxic effect on the developing brain of young smokers, again from the study
Prevention and policy efforts should focus on delivering to the public the message that cannabis use during adolescence can have harmful effects on neuropsychological functioning, delaying the onset of cannabis use at least until adulthood, and encouraging cessation of cannabis use particularly for those who began using cannabis in adolescence.
You can read the research findings in the latest issue of Proceedings of the National Academy of Science