Is cannabis smoking more harmful than cigarette smoking?
Tuesday, July 31, 2007
Jonathan Foulds, MA, MAppSci, PhD
Firstly, we can’t ignore the fact that in most places and circumstances possession of cannabis is a criminal offence with potentially serious legal consequences and testing positive for cannabis use in the workplace can seriously harm your career. That being said, it is difficult to tease out the health effects of cannabis smoking, partly because almost all cannabis smokers are or have been tobacco smokers as well. The recent study compared lung effects on four groups, each consisting of around 80 volunteers: 1. Cannabis users (at least a joint a day for 5 years), 2. Cigarettes only smokers (at least 20 per day for at least a year), 3. Those who smoke both cigarettes and cannabis and 4. Never smokers. When they scanned the lungs for evidence of emphysema they found that only 1% of the cannabis only users had emphysema, as did 19% of the cigarette smokers, 16% of those using both cigarettes and cannabis and 0% of the never smokers. This appears to show that although cannabis smoking worsens lung function, structural damage is common only with cigarette smoking. This finding likely reflects the different ways in which the products are used. A cannabis joint is typically smoked with greater intensity, with larger puff volumes and breath holding, leading to greater smoke and carbon-monoxide exposure than from a single cigarette (hence the greater impact on lung function on a per-smoke basis). However, while most regular cannabis smokers will smoke less than 5 joints per day, most regular cigarette smokers will typically smoke over 15 cigarettes per day. So the overall smoke exposure is typically much greater with tobacco than with cannabis and this is a likely reason for the greater occurrence of tobacco-caused illness.
Chronic cannabis use is associated with the following health effects:
Increased risk of developing a psychotic illness
Respiratory diseases (e.g. bronchitis) and impaired lung function
Dependence (and an associated withdrawal syndrome)
Subtle disturbances of memory and attention
Cannabis use may also be associated with other health problems (e.g. lung cancer, and birth defects in children whose mother smoked cannabis during pregnancy) but the evidence is less clear for these problems.
Tobacco smoking, on the other hand, has been proven to cause a long list of diseases, including the three main causes of premature death: lung cancer, COPD and cardiovascular diseases. The status of tobacco as a legal form of drug use, its less marked psychological effects (e.g. not impairing judgment and driving ability), and the relatively short half-life of the active ingredient (nicotine half-life= 2 hours, versus days for THC) all lead to the tendency for users to take it very frequently (e.g. 15-20 cigarettes per day) and for a very long time (typically starting in teenage years and continuing daily into old age). Cannabis, on the other hand, is more commonly used either less than daily or once or twice per day, and users typically cease use prior to middle age.
So if one is to compare the health effects under typical use conditions, tobacco smoking is much more harmful to health. However, if one were to compare the effects on a “per smoke” basis then the two are likely of similar harmfulness, with cannabis having greater adverse psychological effects.
The human body was not built to inhale smoke of any kind, and whether it’s the result of burning tobacco, cannabis or lettuce, inhalation will cause damage in proportion to the quantity inhaled.
7 Comments:
At Fri Aug 10, 02:16:00 AM 2007,
West Stand Upper said…
You know, I think it would be interesting to find the pscyhological effects of tabacco use. I know that smoking heavily made me far, far more neurotic and passive than now when I don't smoke. Smoking is something that takes healthy pain away which is unhealthy, I s'pose.
At Mon Aug 13, 03:37:00 PM 2007,
Jonathan Foulds, MA, MAppSci, PhD said…
Dear West Stand Upper,
Actually there have been quit alot of studies of the psychological effects of nicotine and tobaco use. One interesting finding is that smokers as a group report being more stressed than non-smokers, and smokers who quit then report being less stressed. Sounds consistent with your experience.
Another interesting finding is that while nicotine does not calm people down, it does produce a small improvement in concentration and reaction time (a bit like caffeine). I think you are right that smokers often have a cigarette when they feel stressed, but that may not help them get to the root of the problem causing the stress. Like other drugs, it may just help numb the emotions a little. For some people an important part of quitting smoking is learning to deal with problems directly rather than going outside for a smoke. Not always easy!
If you are interested in reading more on the psychological effects of tobacco/nicotine there is an excellent section in the English Royal college of Physicians Report on Nicotine Addiction:
http://www.rcplondon.ac.uk/pubs/books/nicotine/
At Wed Sep 05, 08:16:00 AM 2007,
Anonymous said…
IS hookah smoking more harmful than cigarette smoking????
At Tue Oct 23, 11:49:00 PM 2007,
Anonymous said…
I often find a tremendous flaw in reading these studies, in that, they control for tobacco cigarettes and cannabis cigarettes, but always seem to neglect to mention the controlling for these fundamental variables–the amount of cannabis per cigarette; the amount of tobacco per cigarette; whether the individuals were inhaling with a filter or if it was a rolled tobacco cigarette, much in the same fashion that cannabis is rolled. Another fascinating notion is the fact that there is little discussion about the various methods of delivering a dose of THC to the body. It is often common for individuals to engage in the smoking process through PAPERLESS devices that are know such as: Vaporizers, water-pipes and pipes, along with many other various apparatuses. It is even common for people to digest it through brownies. So I am suggesting that one produces a study demonstrating the affects of cannabis through a nonpaper apparatus. A standard of measurement could be drawn from my daily intake of cannabis. I smoke aprox. (.25) grams in a nice tear-drop shaped pipe. Remember, to use matches made in America!!!
At Thu Nov 22, 06:51:00 AM 2007,
Anonymous said…
"Remember, to use matches made in America!!!"
So much for your paper-free kit.
At Thu Dec 11, 04:30:00 AM 2008,
tanmann said…
ok so im 16 and i have anxiety and depression. its been acting up alot lately and also so has my add, to the point where ive been getting new ticks and less concentration almost everyday. I went and smoked marijuana with my friend and for two weeks following my concentraion went up and my ticks went away. But i was worried because i didnt know if in the long run the help would hurt. what this sounds like to me is that the rate at which i smoke marijuana (once every 1-2 weeks) there would be almost no big consequences except maybe slightly decreased lung capacity. What do you all think? Im actually thinking about asking a physician or other doctor.
At Sun Dec 14, 06:52:00 PM 2008,
Jonathan Foulds, MA, MAppSci, PhD said…
If you are 16 and have anxiety, depression and ADD and have started using marijuana, then I think its an excellent idea to go and discuss things with your doctor. These are all things that can be helped.
I seriously doubt that marijuana is the answer. Marijuana generally does not help with mental concentration...it generally has quite the opposite effect. And while the article I was discussing focussed on lung function, that is not the only health effect of smoking marijuana...it causes a number of illnesses like smoking tobacco...including lung cancer.
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