Marijuana doesn't harm lung function, study found
Smoking a joint once a week or a bit more apparently doesn't harm the lungs, suggests a 20-year study that bolsters evidence that marijuana doesn't do the kind of damage tobacco does.
The results, from one of the largest and longest studies on the health effects of marijuana, are hazier for heavy users — those who smoke two or more joints daily for several years. The data suggest that using marijuana that often might cause a decline in lung function, but there weren't enough heavy users among the 5,000 young adults in the study to draw firm conclusions....
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...The analyses showed pot didn't appear to harm lung function, but cigarettes did. Cigarette smokers' test scores worsened steadily during the study. Smoking marijuana as often as one joint daily for seven years, or one joint weekly for 20 years was not linked with worse scores. Very few study participants smoked more often than that.
Having worked closely with chemically addicted patients in a rehabilitation situation, I can say that prior marijuana abuse is so prevalent among those who hit rock bottom on harder drugs, that it is almost like a prerequisite. Those who claim it is not a gateway drug because so many people use it without graduating to other drugs miss the point that among those who DO ruin their lives on harder drugs, habitual prior pot use is nearly universal. Pot breaks down the barrier to doing harmful and illegal drugs, and the relatively benign consequences open the door to believing that other drugs will be just as benign. What I have seen with my own two eyes tells me that pot is a gateway drug in spite of all the protestation to the contrary from legalization advocates.
I do think the so-called "war" on pot use has been lost for years. I think current laws place casual users in prison where they don't belong, and create a black-market and all the crime that goes with it. Something needs to change, and I fear that legalization is starting to make the most sense if we ever want to dismantle the criminal cartels.
But all that said, it is interesting (insofar as this study is accurate) to learn that marijuana use has little negative effect on the lungs. That seems counter-intuitive. Some possible reasons for the differences between tobacco and marijuana's effects on the lungs are suggested at the link, but nothing conclusive.