1. Marijuana Causes Brain Damage
The most celebrated study that claims to show brain damage is the rhesus monkey study of Dr. Robert Heath, done in the late 1970s. This study was reviewed by a distinguished panel of scientists sponsored by the Institute of Medicine and the National Academy of Sciences.
Their results were published under the title, Marijuana and Health in 1982.
Heath's work was sharply criticized for its insufficient sample size (only four monkeys), its failure to control experimental bias, and the misidentification of normal monkey brain structure as "damaged".
Actual studies of human populations of marijuana users have shown no evidence of brain damage.
For example, two studies from 1977, published in the Journal of the American Medical Association (JAMA) showed no evidence of brain damage in heavy users of marijuana.
That same year, the American Medical Association (AMA) officially came out in favor of decriminalizing marijuana. That's not the sort of thing you'd expect if the AMA thought marijuana damaged the brain.
2. Marijuana Damages The Reproductive System
This claim is based chiefly on the work of Dr. Gabriel Nahas, who experimented with tissue (cells) isolated in petri dishes, and the work of researchers who dosed animals with near-lethal amounts of cannabinoids (i.e., the intoxicating part of marijuana.
Nahas' generalizations from his petri dishes to human beings have been rejected by the scientific community as being invalid.
In the case of the animal experiments, the animals that survived their ordeal returned to normal within 30 days of the end of the experiment.
Studies of actual human populations have failed to demonstrate that marijuana adversely affects the reproductive system.
3. Marijuana Is A "Gateway" Drug It Leads To Hard Drugs
This is one of the more persistent myths. A real world example of what happens when marijuana is readily available can be found in Holland.The Dutch partially legalized marijuana in the 1970s. Since then, hard drug use, heroin and cocaine, have DECLINED substantially.
If marijuana really were a gateway drug, one would have expected use of hard drugs to have gone up, not down.
This apparent "negative gateway" effect has also been observed in the United States.
Studies done in the early 1970s showed a negative correlation between use of marijuana and use of alcohol.
A 1993 Rand Corporation study that compared drug use in states that had decriminalized marijuana versus those that had not, found that where marijuana was more available, the states that had decriminalized, hard drug abuse as measured by emergency room episodes decreased.
In short, what science and actual experience tell us is that marijuana tends to substitute for the much more dangerous hard drugs like alcohol, cocaine, and heroin.
4. Marijuana Suppresses The Immune System
Like the studies claiming to show damage to the reproductive system, this myth is based on studies where animals were given extremely high, in many cases, near-lethal, doses of cannabinoids.
These results have never been duplicated in human beings. Interestingly, two studies done in 1978 and one done in 1988 showed that hashish and marijuana may have actually stimulated the immune system in the people studied.
5. Marijuana Is Much More Dangerous Than Tobacco
Smoked marijuana contains about the same amount of carcinogens as does an equivalent amount of tobacco.
It should be remembered, however, that a heavy tobacco smoker consumes much more tobacco than a heavy marijuana smoker consumes marijuana.
This is because smoked tobacco, with a 90% addiction rate, is the most addictive of all drugs while marijuana is less addictive than caffeine.
Two other factors are important. The first is that paraphernalia laws directed against marijuana users make it difficult to smoke safely.
These laws make water pipes and bongs, which filter some of the carcinogens out of the smoke, illegal and, hence, unavailable.
The second is that, if marijuana were legal, it would be more economical to have cannabis drinks like Bhang (a traditional drink in the Middle East) or tea which are totally non-carcinogenic.
This is in stark contrast with "smokeless" tobacco products like snuff which can cause cancer of the mouth and throat.
When all of these facts are taken together, it can be clearly seen that the reverse is true: marijuana is much SAFER than tobacco.
6. Legal Marijuana Would Cause Carnage On The Highways
Although marijuana, when used to intoxication, does impair performance in a manner similar to alcohol, actual studies of the effect of marijuana on the automobile accident rate suggest that it poses LESS of a hazard than alcohol.
When a random sample of fatal accident victims was studied, it was initially found that marijuana was associated with RELATIVELY as many accidents as alcohol.
In other words, the number of accident victims intoxicated on marijuana relative to the number of marijuana users in society gave a ratio similar to that for accident victims intoxicated on alcohol relative to the total number of alcohol users.
However, a closer examination of the victims revealed that around 85% of the people intoxicated on marijuana WERE ALSO INTOXICATED ON ALCOHOL.
For people only intoxicated on marijuana, the rate was much lower than for alcohol alone. This finding has been supported by other research using completely different methods.
For example, an economic analysis of the effects of decriminalization on marijuana usage found that states that had reduced penalties for marijuana possession experienced a rise in marijuana use and a decline in alcohol use with the result that fatal highway accidents decreased.
This would suggest that, far from causing "carnage", legal marijuana might actually save lives.
7. Marijuana "Flattens" Human Brainwaves
This is an out-and-out lie perpetrated by the Partnership for a Drug-Free America.
A few years ago, they ran a TV ad that purported to show, first, a normal human brainwave, and second, a flat brainwave from a 14-year-old "on marijuana".
When researchers called up the TV networks to complain about this commercial, the Partnership had to pull it from the air.
It seems that the Partnership faked the flat "marijuana brainwave".
In reality, marijuana has the effect of slightly INCREASING alpha wave activity. Alpha waves are associated with meditative and relaxed states which are, in turn, often associated with human creativity.
8. Marijuana Is More Potent Today Than In The Past
This myth is the result of bad data. The researchers who made the claim of increased potency used as their baseline the THC content of marijuana seized by police in the early 1970s.
Poor storage of this marijuana in non air conditioned evidence rooms caused it to deteriorate and decline in potency before any chemical assay was performed.
Contemporaneous, independent assays of unseized "street" marijuana from the early 1970s showed a potency equivalent to that of modern "street" marijuana.
Actually, the most potent form of this drug that was generally available was sold legally in the 1920s and 1930s by the pharmaceutical company Smith-Klein under the name, "American Cannabis".
9. Marijuana Impairs Short Term Memory
This is true but misleading. Any impairment of short-term memory disappears after a few hours, when one is no longer under the influence of marijuana.
Often, the short-term memory effect is paired with a reference to Dr. Heath's poor Rhesus monkeys to imply that the condition is permanent.
10. Marijuana Lingers In The Body Like DDT
This is also true but misleading. Cannabinoids are fat soluble as are innumerable nutrients and, yes, some poisons like DDT.
For example, the essential nutrient, Vitamin A, is fat soluble but one never hears people who favor marijuana prohibition making this comparison.
11. There Are Over A Thousand Chemicals In Marijuana Smoke
Again, true but misleading. The 31 August 1990 issue of the magazine Science notes that of the over 800 volatile chemicals present in roasted COFFEE, only 21 have actually been tested on animals and 16 of these cause cancer in rodents.
Yet, coffee remains legal and is generally considered fairly safe.
12. No One Has Ever Died Of A Marijuana Overdose
This is true. It was put in to see if you are paying attention. Animal tests have revealed that extremely high doses of cannabinoids are needed to have lethal effect.
This has led scientists to conclude that the ratio of the amount of cannabinoids necessary to get a person intoxicated (i.e., stoned) relative to the amount necessary to kill them is 1 to 40,000.
In other words, to overdose, you would have to consume 40,000 times as much marijuana as you needed to get stoned.
In contrast, the ratio for alcohol varies between 1 to 4 and 1 to 10. It is easy to see how upwards of 5000 people die from alcohol overdoses every year and no one EVER dies of marijuana overdoses.
13. Marijuana use tied to testicular cancer? This is the new scare of 2009, but readers Los Angeles Times aren't so sure.
Feb 13 2009 - A controversial new study, posted on the Booster Shots blog Feb. 9, reports a connection between pot use in young males and testicular cancer. The study, and the post, were mostly greeted with extreme skepticism from readers. Comments ranged from alleging government conspiracy to suggesting that this was merely reactionary publishing in the wake of the controversial Michael Phelps bong photo.
Joseph said: Any institution wanting to do a study on the effects of marijuana needs to go through the U.S. Government to have samples released for testing. Remember, marijuana is federally illegal to possess. This includes scientific studies as well. Whenever the U.S. Government has oversight and control over a study on anything, they tend to make the results fit their predetermined agenda, especially when it comes to the subject of marijuana. I am not a smoker, and yet I find this coincidently-timed pile of BS just another attempt to insult the intelligence of the American people. Marijuana has been used for thousands of years by many cultures, and as far as I can tell, with 6.5 billion people on this planet and growing, it hasn’t affected reproductive organs one iota.
Chrissy said: So, we have known for how many years that cigarettes cause far worse problems, and still nothing is done about it. If Phelps had been pictured smoking a cigarette no body would have thought twice about it.
Medical Marijuana is being used not to FIGHT cancer, but to help cancer patients get through the tough treament by mitigating nausea, appetite loss, pain and anxiety. It can also be used in less harmful ways than smoking, such at through a vaporizer or ingestion.
As a substance that has proven to be less harmful than tobacco, it's way past time to legalize it.
PR. Opaganda said: of the 80 or so million who have smoked cannabis what percentage of those have any form of testicular cancer? propaganda ......shame shame L.A. Times. If this were true most of them would ...bad LA times BAD!
Some readers argued the scientific methods in the report were flawed... their comments after the jump:
Christine said: As a scientist, I find it appalling that these types of studies keep making headlines. What about uncontrolled variables? This is a huge unexplained source of variation. The fact of the matter is that most pot is grown with numerous pesticides, fungicides, and “inert” ingredients such as nonylphenol that have been shown to be hormonally active and dramatically significant. See, for example, www.ourstolenfuture.org. Also, there was a story recently about Mexican drug cartels growing pot in the Redwood forests using major amounts of pesticides, but did the authors correct for this? Answer: No.
Until these “scientists” start being a lot more honest about their sources and methods, I think we can call this obfuscation and subterfuge. And yes, there is an ulterior motive.
Jake said: but before all of you guys start bashing Marijuana you might want to read the whole thing. "The findings were independent of known risk factors such as undescended testes and a family history of testicular cancer". Thats with anything this study has nothing to do with marijuana is it just another way to get marijuana as the bad drug. If your family has had a history of a bad liver are we gonna say that from alcohol? If you have a family history of a disease then you are going to be more likely to get it. Nothing to do with marijuana its just alot of people that smoke it so yeah there will be bull studies like this that come out. I say you do studies on alcohol and tobacoo, them to substances are far worst them marijuana and marijuana has medical value. legalize it, give america the billions of dollers each year to help us out of this whole we are in.
Alex M said: You can't rely on self-reporting to study Marijuana. First, what one person smokes as Marijuana may contain different compounds than the Marijuana that another person smokes. They may have been grown with different fertilizers, different water, etc. The Cannabis these people smoked could have different cannabanoids in different varieties as well.
More junk science.
There were a few, however, who found the study worthwhile.
Bob1421 said: I have a friend who is 52 years old and dying of "COPD' directly related to smoking weed all of his life. So to all you smokers who think weed is harmless i say, "Light up and get happy."
Jeff said: I have long experience working with people with drug problems. I have noticed that they often refuse to believe what is obvious; they ignore evidence when it is right before them; they attack the messenger; and they are very paranoid. It would be laughable that so many respondents have attacked the Times, or the researchers that the Times is reporting on, for reporting that smoking marijuana may be bad--it would be laughable if it weren't so sad. Don't believe them, Times: not everyone smokes, not everyone agrees that marijuana is harmless, and certainly not everyone thinks that the release of another study showing the dangers of breathing smoke (from whatever source) is part of an evil conspiracy.
Bruce said: Most of you are being rather shortsighted. There are associated risks with doing/consuming many things in this world. You can make all the assumptions you want about the timing/why this information was published. In the end, it's information that may permit some people to make an educated decision about whether they want to use/smoke the stuff or not.
So what do you think? Government conspiracy? Poor science? Legalize pot? Or is this a legitimate black eye against marijuana?
1) Marijuana and Health, Institute of Medicine, National Academy of Sciences, 1982. Note: the Committee on Substance Abuse and Habitual Behavior of the "Marijuana and Health" study had its part of the final report suppressed when it reviewed the evidence and recommended that possession of small amounts of marijuana should no longer be a crime (TIME magazine, July 19, 1982). The two JAMA studies are: Co, B.T., Goodwin, D.W., Gado, M., Mikhael, M., and Hill, S.Y.: "Absence of cerebral atrophy in chronic cannabis users", JAMA, 237:1229-1230, 1977; and, Kuehnle, J., Mendelson, J.H., Davis, K.R., and New, P.F.J.: "Computed tomographic examination of heavy marijuana smokers", JAMA, 237:1231-1232, 1977.
2) See Marijuana and Health, ibid., for information on this research. See also, Marijuana Reconsidered (1978) by Dr. Lester Grinspoon.
3) The Dutch experience is written up in "The Economics of Legalizing Drugs", by Richard J. Dennis, The Atlantic Monthly, Vol 266, No. 5, Nov 1990, p. 130. See "A Comparison of Marijuana Users and Non-users" by Norman Zinberg and Andrew Weil (1971) for the negative correlation between use of marijuana and use of alcohol. The 1993 Rand Corporation study is "The Effect of Marijuana Decriminalization on Hospital Emergency Room Episodes: 1975 - 1978" by Karyn E. Model.
4) See a review of studies and their methodology in "Marijuana and Immunity", Journal of Psychoactive Drugs, Vol 20(1), Jan-Mar 1988. Studies showing stimulation of the immune system: Kaklamani, et al., "Hashish smoking and T- lymphocytes", 1978; Kalofoutis et al., "The significance of lymphocyte lipid changes after smoking hashish", 1978. The 1988 study: Wallace, J.M., Tashkin, D.P., Oishi, J.S., Barbers, R.G., "Peripheral Blood Lymphocyte Subpopulations and Mitogen Responsiveness in Tobacco and Marijuana Smokers", 1988, Journal of Psychoactive Drugs, ibid.
5) The 90% figure comes from Health Consequences of Smoking: Nicotine Addiction, Surgeon General's Report, 1988. In Health magazine in an article entitled, "Hooked, Not Hooked" by Deborah Franklin (pp. 39-52), compares the addictiveness of various drugs and ranks marijuana below caffeine. For current information on cannabis drinks see Working Men and Ganja: Marijuana Use in Rural Jamaica by M. C. Dreher, Institute for the Study of Human Issues, 1982, ISBN 0-89727-025-8. For information on cannabis and actual cancer risk, see Marijuana and Health, ibid.
6) For a survey of studies relating to cannabis and highway accidents see "Marijuana, Driving and Accident Safety", by Dale Gieringer, Journal of Psychoactive Drugs, ibid. The effect of decriminalization on highway accidents is analyzed in "Do Youths Substitute Alcohol and Marijuana? Some Econometric Evidence" by Frank J. Chaloupka and Adit Laixuthai, Nov. 1992, University of Illinois at Chicago.
7) For information about the Partnership ad, see Jack Herer's book, The Emperor Wears No Clothes, 1990, p. 74. See also "Hard Sell in the Drug War", The Nation, March 9, 1992, by Cynthia Cotts, which reveals that the Partnership receives a large percentage of its advertising budget from alcohol, tobacco, and pharmaceutical companies and is thus disposed toward exaggerating the risks of marijuana while downplaying the risks of legal drugs. For information on memory and the alpha brainwave enhancement effect, see "Marijuana, Memory, and Perception", by R. L. Dornbush, M.D., M. Fink, M.D., and A. M. Freedman, M.D., presented at the 124th annual meeting of the American Psychiatric Association, May 3-7, 1971.
8) See "Cannabis 1988, Old Drug New Dangers, The Potency Question" by Tod H Mikuriya, M.D. and Michael Aldrich, Ph.D., Journal of Psychoactive Drugs, ibid.
9) See Marijuana and Health, ibid. Also see "Marijuana, Memory, and Perception", ibid.
10) The fat solubility of cannabinoids and certain vitamins is well known. See Marijuana and Health, ibid. For some information on vitamin A, see "The A Team" in Scientific American, Vol 264, No. 2, February 1991, p. 16.
11) See "Too Many Rodent Carcinogens: Mitogenesis Increases Mutagenesis", Bruce N. Ames and Lois Swirsky Gold, Science, Vol 249, 31 August 1990, p. 971.
12) Cannabis and alcohol toxicity is compared in Marijuana Reconsidered, ibid., p. 227. Yearly alcohol overdoses was taken from "Drug Prohibition in the United States: Costs, Consequences, and Alternatives" by Ethan A. Nadelmann, Science, Vol 245, 1 September 1989, p. 943. -- paul hager email@example.com "The most formidable weapon against errors of every kind is reason." -- Thomas Paine, _The Age of Reason
13) Ben Taylor for Los Angeles Times, CA - Feb 13, 2009