Legalize it? Medical evidence on marijuana blows both ways

May 25, 2009 By Sam McManis

Sparked anew by Gov. Arnold Schwarzenegger's call for the state to study the legalization of marijuana, both sides in the smoldering pot debate point to research to bolster their positions.

Such recitation of conflicting studies can be manipulated and selected buffet-style to serve whatever political and health agenda is being touted.

Even governmental findings can be contradictory. In 1999, for instance, the Office of National Drug Control Policy asked the Institute of Medicine to review evidence. The institute found that, "except for the harms associated with smoking, the adverse effects of marijuana use are within the range of effects tolerated for other medications."

Yet in 2006, the ruled that marijuana has no health benefits and has known and proven harms. It is classified a Schedule 1 drug -- the highest risk of addiction -- in the Controlled Substances Act.

Wading through the medical literature, though, makes those conclusions less cut and dried.

"When I was a resident in Kaiser in San Francisco in 1978, I gave a lecture to physicians on marijuana, and I remember my conclusion at that time was that you can find in the literature whatever you were looking for," says Dr. Donald Abrams, a University of California, San Francisco, oncologist and leading medical marijuana researcher. " 'Marijuana is good for asthma.' 'Marijuana's bad for asthma.' 'Marijuana causes schizophrenia.' 'Marijuana (decreases) schizophrenia.' And, you know, the evidence is still like that."

There are many factors, of course. As noted by UCLA pulmonologist Dr. Donald Tashkin, who has studied marijuana's effects on the lungs for three decades, "That's just the nature of medical science. You have to deal with variability. The population studied may be different or the methods used to study may differ."

Yet when the arguments for legalization of marijuana, both for medicinal and recreational use, are put forth, solid medical science often gets clouded in an ideological haze.

"Although we like to say we separate politics from science, with medical marijuana, that's really difficult," Abrams says. "It depends on who does the study, where it's published and what their agenda is."

Bearing in mind those caveats, here is a look at the research on marijuana's effect in areas critical to health.


UCLA's Tashkin studied heavy marijuana smokers to determine whether the use led to increased risk of lung cancer and chronic obstructive pulmonary disease, or COPD. He had hypothesized that there would be a definitive link between cancer and marijuana smoking, yet the results proved otherwise.

"What we found instead was no association and even a suggestion of some protective effect," says Tashkin, whose research was the largest case-control study ever conducted. The study was funded by the National Institutes of Health.

Tobacco smokers in the study had as much as a 21-fold increase in lung cancer risk. Cigarette smokers, too, developed COPD more often in the study, and researchers found that marijuana did not impair lung function.

Tashkin, supported by other research, concluded that the active ingredient tetrahydrocannabinol, or THC, has an "anti-tumoral effect" in which "cells die earlier before they age enough to develop mutations that might lead to lung cancer."

However, the smoke from marijuana did swell the airways and lead to a greater risk of chronic bronchitis.

"Early on, when our research appeared as if there would be a negative impact on lung health, I was opposed to legalization because I thought it would lead to increased use and that would lead to increased health effects," Tashkin says.

"But at this point, I'd be in favor of legalization. I wouldn't encourage anybody to smoke any substances, because of the potential for harm. But I don't think it should be stigmatized as an illegal substance.

"Tobacco smoking causes far more harm. And in terms of an intoxicant, alcohol causes far more harm."

Cognitive function

A 2006 study in the journal Neurology found that speed of thinking, attention and verbal fluency were affected as much as 70 percent by long-term heavy use (four or more joints per week).

But a 2003 review of literature in the Journal of the International Neuropsychological Society found that marijuana smoking had a "small effect" on memory in longtime users.

However, users had no lasting effects in reaction time, attention or verbal function.

"Surprisingly, we saw very little evidence of deleterious effects," Dr. Igor Grant, researcher at the University of California, San Diego, School of Medicine, said in a statement.

Other studies: A 2002 study in the Journal of the American Medical Association found that heavy users did worse on recall memory tests. A 2006 study in Greece showed users had slower mental-processing speed than the control group.

Then again, a 2007 study at the University of Lausanne in Switzerland, published in Archives of Pediatrics & Adolescent Medicine, found that students who smoked marijuana had better grades than those who used only tobacco or those who did not smoke any substance.

In terms of brain development, a 2000 study in the Journal of Addictive Diseases found changes in brain structure in those who started using marijuana before age 17 but not in those who started at an older age.

A 2009 Children's Hospital of Philadelphia study used brain imaging to show that heavy adolescent users are more likely to have disrupted brain development in regions involving memory, attention, decision making and language.

But a 2008 Ohio State University study found that marijuana can reduce brain inflammation and perhaps reduce memory impairment that could delay Alzheimer's disease.


Yes, there is an increased risk in psychotic behavior and long-term risk of mental illness from marijuana use, according to a 2007 review of literature commissioned by Great Britain's Department of Health and published in the Lancet.

But the risk is small, because the risk of developing psychosis in the general population is 3 percent over a lifetime and rises to 5 percent for marijuana users, lead researcher Stanley Zammit told the Los Angeles Times. "So 95 percent of the people are not going to get psychotic, even if they smoke on a daily basis," he told the paper.

In 2005, New Zealand researchers studied a group of people with a gene variant the researchers believe predisposes that group to developing psychosis. Those in the group who smoked marijuana as teens had a tenfold increase in risk of psychosis than those who abstained.


A study published in 2001 in the American Journal of Psychiatry followed nearly 2,000 adults over 15 years. It found that marijuana users who had no symptoms of depression at the start were four times more likely than non-users of developing symptoms during that time frame.

In 2008, the U.S. Office of National Drug Control Policy stated that early marijuana use could increase the likelihood of mental illness by as much as 40 percent later in life.

However, researchers at McGill University in Montreal in 2007 reported in the Journal of Neuroscience that THC in low doses actually serves as an antidepressant similar to Prozac, producing serotonin. At higher doses, however, they found it could lead not only to depression but also to psychotic episodes.


(c) 2009, The Sacramento Bee (Sacramento, Calif.).
Visit The Sacramento Bee online at
Distributed by McClatchy-Tribune Information Services.

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5 / 5 (9) May 25, 2009
If you do research with a pre-conceived idea of what you will find, that isn't science. And that is the only research the US Govt has allowed for the last 40 years.

This news just in, your govt (the ONDCP in particular) is lying to you. They are in the propaganda business. They are owned by corporations, including the drug companies, who can't profit from hemp.
5 / 5 (7) May 25, 2009
just legalize it already. if the president really wants to go down in history, he'll do it...but as ive heard somewhere before and agree with, that sort of thing is a 2nd term coming to an end type of law....
5 / 5 (5) May 26, 2009
Very nice article, exemplary for many issues.
4.6 / 5 (5) May 26, 2009
This whole issue is about jobs and money, not facts or what is least harmful for society overall. If maryjane is legalized many federal and other employees will lose their jobs and federal fundings will be cut back. Under the table payouts will also go down. All not very popular w/ those in power.
4.2 / 5 (10) May 26, 2009
Points to ponder:

1. The question "Is MJ bad for society?" is typically used by spin doctors to defend drug laws by avoiding the question "are laws against MJ worse for society than is MJ?"

2. Drug laws are the sole thing that keeps the price of those drugs so high, which is the sole cause of drug cartels and pushers, and the primary financier of terrorism. And each of those destroys orders of magnitude more lives than do the drugs, themselves - even in the case of very hard drugs.

3. Drug law enforcement directly destroys many thousands of lives every year. Besides botched and wrong-house drug raids and just general corruption and miscarriages of justice (which are rampant, by the way), so called "correctional facilities" by and large only serve to teach young inmates more antisocial behavior. Having been caught smoking MJ is actually rather stylish in many subcultures.

4. Because recreational drugs are illegal, users of recreational drugs must join the ranks of criminals. A teenager that smokes pot eventually gets involved with the wrong crowd not because pot made him do it, but because drug laws caused pot use to be intimately associated with that wrong crowd. If video games were illegal, then video game use would make all its users become part of the criminal subculture. Additionally, the result is that society in general believes the lie that pot causes criminal activity.

5. Every remotely reputable study and statistic that has ever compared alcohol (or tobacco) to marijuana has proven alcohol/tobacco is orders of magnitude more damaging to society than is marijuana. EVERY single study. And we're talking a long list of organizations starting with Ivy league schools, the AMA, the CDC, etc.. 'Course, we don't need no stinking actual science because we already found out the truth from taxpayer funded "your brain on drugs" TV ads (although perhaps they are simply trying to obey that famous amendment of the U.S. Constitution requiring the federal government to use taxpayer dollars to create social propaganda--sorry I can't quite remember which amendment it is, at the moment).

6. In most states, punishment for growing one marijuana plant is notably more severe than the punishment for raping a child.

7. Which of the following two groups most wants marijuana to remain as illegal as possible: Drug cartels or the people of the United States? (one might want to review some polling data before answering)

8. Maybe the defenders of drug laws can also explain why a CIA jet was found laden with four tons of cocaine.

9. All statistics and studies designed to measure the success of the drug war prove it is failing miserably. The usage rates have remained the same for the last several decades, and it has directly cost taxpayers many billions. (Not to mention it has indirectly cost them many more billions and many lives).

10. How is prohibition of MJ different from prohibition of alcohol in the 1920s? Answer: Alcohol is far more damaging to society, and its prohibition only lasted a handful of years instead of many decades.

11. The real reason alcohol and tobacco are legal is simply that half our legislators are addicted to them. And the reason they are addicted to them and not marijuana is that marijuana is not addictive ('course I admit I'm again getting this info from those silly, unreliable sources like the AMA, Ivy-league universities, and the CDC. Perhaps I need to watch more taxpayer-funded propaganda.)

5 / 5 (8) May 26, 2009
Look for the hand of the Rockefeller(banking and corporate), skull and bones and the CIA (neocons-nazi) in anything having to do with the vilifying of marijuana.

Then go look at who runs the US prisons for profit, who created the 'drug laws', and are involved in drug running in countries all across the world-mostly in countries that the US military has a presence or interest in, as well.

If the US returns to a constitutional democratically elected government system with all corporate fascist influence removed from the US government system, then you might have a real world to live in. Right now the US is a fascist joke and it's getting dangerously uglier every day.

With one out of ever 29 US citizens in the jail system(!!!!), compared to Canada's one in 912 citizens(!!!!!), you KNOW something is incredibly ~FUCKED~.

Just spend two seconds thinking about that.

People like to think about how many people were imprisoned in Nazi Germany as a 'ratio of imprisoned to free'.

Guess what?

The US is currently ~WELL BEYOND~ that ratio.
5 / 5 (6) May 26, 2009
Good article, great posts. Legalize it, tax it, balance the %^%$ing budget.

Thank you.
5 / 5 (3) May 26, 2009
Go Arnie! Who'd have thought a body building actor would turn into such a level headed politician in regards to weed? It will be interesting to see the results of an unbiased political investigation into mj. It'll certainly be a 1st!
5 / 5 (5) May 26, 2009
The sad state of the matter is that the general quality of politicians is notably lower than the average guy on the street. So its fairly easy for a reasonably intelligent actor/bodybuilder to do a far better job compared to those other slime-balls. Its not surprising that the dredges of society (often having inferiority complexes for good reason!) would spend the most energy pursuing a career in politics. My favorite dream is Ron Paul president and Arnie the majority leader. Alas that will never happen, because the vast majority of the people of the U.S. are incapable of grasping concepts more complex than "me hungry now" or "president promise to print more money for us, yay!".

5 / 5 (1) May 26, 2009
For national security and neurochemical stability (CYP450 Inhibition and Dopamine antagonism) having access to more avenues of medicine is better than not. Recreation requires safety, commerce requires safety.

Leaving it open to debate is a bonfire waiting to destroy the continental U.S., simply put a few kids getting fucked up then treated and hospitalized is better than a country being thrown into chaos.
5 / 5 (5) May 26, 2009
fleem is right on target. The trouble is that government has always been about profit and not about public service. They will always justify what they do by declaring we are creating or saving jobs and that is far more important for the public good. We are not supposed to notice that the playing field is not level for the rest of us as they rig the game.

State and local law enforcement agencies could not even survive without the funds they receive for drug enforcement.

Privatizing the prison system was also not a good idea in the name of justice. Now corporations run the prisons and they do not get paid for empty beds.
5 / 5 (7) May 26, 2009
This weekend, I admittedly was incredibly high for great periods of time (we pinned memorial day weekend as an excuse). My friends and I had great conversations on several topics, we all got along great, we went for walks around the city, we might have had the occasional giggle fit, but I woke up this morning completely refreshed and feeling great.

If I had instead used alcohol this weekend, it might have been a different story. There would have been no decent conversation, just mumbling or half completed sentenced that are slurred beyond recognition. There could have very well been fights or uncomfortably aggressive arguments. We would have never successfully completed a walk around the city; We might have been able to stumble through the city, hurting and embarrassing ourselves, but no leisurely walking.
Finally, I most certainly would not have awoken this morning with a refreshed feeling. I might have woken up with a brand new STD, nausea, vomiting, headache, stomach ache. The room might be spinning so fast it makes me want to retire under the covers for the day.

Weed and alcohol are two incomparable substances. It's nonsense that weed is illegal.
5 / 5 (2) May 27, 2009
I think if more than half of the united states says that we want something, regardless of what our government thinks shouldn't they still uphold democracy in witch thousands of solders fought and died for to protect. WE VOTED
5 / 5 (2) May 27, 2009

I beg to differ here....exactly what employees would lose their jobs due to legalization, and exactly what federal funding would be cut? I'm sure there are valid examples, but I bet the gain both financially for the government (as archivis put it; to fix this fkn recession), economically for the people, AND, theres a HUGE level of motivation, so to speak, it would put into people due to the government doing whats right for citizens and not whats right for our increasingly socialist and communist combination government to stay in power.

If anything, legalization will create jobs, my examples:

1. factories will need builtand or restructured to make the product (say, packs of cigaweed like cigs)-this makes jobs

2. a whole new FDA element will need to be created to supervise the product, or an existing dept will need to increase jobs

3. inspectors will need hired for the facilities and for the product

4. commercials will need made

5. ads will need placed

....need i go on...I can all day long....

I will however give you that law enforcement may lose some jobs


1. it cant be, more people will be at home enjoying themselves in a healthier way than alcohol can provide, albeit not without risk. not to mention the fact that since everyone has a choice in whether to partake, it wont affect society as a whole either way. I bet if a REAL vote on the legalization for medical and recreational use were to occur nationally, legalization would be a landslide. Most people who don't even smoke don't see a problem with it at all. If you enforce a combination of alcohol and cigarette laws onto marijuana, you have the largest most resourceful and most beneficial resource we could ask for that can make everything. And the best part is, its a weed, and grows as such, and everyone knows the US has no shortage of tons of kinds of weeds just sitting in our front yards alone....

2. I am in complete agreement

3. Again, complete agreement

4. Again....

5. again

6. MOST states carry penalties including life imprisonment and liquidation of all assets, including home and car...but you don't need those where youre the prick lawmakers eyes anyways....OH, theres another job market cut there for ya deatopmg, people who do the paperwork for home foreclosuresafter an arrest... :)

7.thats easy, no poll necessary...if its legal the cartels go bankrupt...

8. I LOVE THIS ONE - and its easy too...its because Bush was president and they hadnt cleaned it out yet. :D I bet Obama told em to just keep it there and give him the jet for personal use :D

9. not to mention the prices of smoke keep going up and up :(

10. there are drunks in congress, the senate, hell, everywhere in the government...they want their alcohol....and most of em probably stopped smoking weed either just after high school/college and entering the professional world, OR, right before their campaign. But I bet 90% did it before :D

11. i should have read this one before i answered #10 :) although i will say, mary may not be physically addicted, but, ones mind does get used to the effects of it...and it does take about a week of not having it before you stop craving it. that is still MUCH better than alcohol or sickness, no shakes...


the nazi's were idiots....nuff said on that. good comments, gave u a 5


sing it brotha


vote schwarzenegger for president :D ammend the laws.....then put his big ass in front of kim jong il in the same room and close the door...i bet n korea stops the nuke program :D


wtf man, no invite...damn.... :D you must not burn much if youre still giggly from it though. i think i got over that at like, what, 12 yrs old :D

if you drank the drink this weekend, you may have had interesting comvos and stuff just like on the cigaweed, BUT, youd forget more of it...alcohol kills cells, weed puts em to least from my understanding...



i wish i could find some damn statistics

Just remember people-

A.N.U.S. (Americans for a New United States)

great aint it....seriously though, i say its time we do what thomas jefferson said (i think it was him)...time to refresh the trees of liberty and have a healthy revolution!!!
5 / 5 (1) May 29, 2009
@brandon - Yes sir. When one stops smoking, over time the brain returns to virtually the same state. The problem with long time smokers (ahem) is simply that with age, brain capacity can lessen naturally... so it can be a little hard to tell :P lol

We should desgin a flag for our A.N.U.S. group... perhaps everyone's favorite leaf surrounded by 50 stars who knows I'm just passin time till lunch.

Refresh the trees... funny considering a guy I know calls herbal smoke "trees" gave me a giggle ;)

I can't help but notice this is the FIRST article I've seen on here with no negative posts or complaining... speaks volumes. While I'm sure there have been others, this is the first I've seen.
not rated yet May 29, 2009
ive never stopped long enough to

I've seriously considered opening a site for the A.N.U.S. movement. Unfortunately, since Bush got into power (Bush 2 that is), he made it illegal to even speak about overthrowing the government. Yet another of many completely unconstitutional laws he enacted. Simpel disagreement between me and the government, they think for the people and by the people means voting...whereas in actuality, at least i my mind, it means if the entire system is corrupt, it cant be for the people and by the people, and therefore should be purged.

And I most definitely agree about both the flag, and the fact we've seen no negative comments so far :D

Just more proof that the majority are ok with it :)
not rated yet May 31, 2009
WE VOTED !! with action already, most people i know smoke/eat MJ or don't care that others do. Imagine if hundreds of thousands gathered together in large assemblies(parking lots,parks,streets,exe.) across the nation at a given time and meeting place to smoked/use MJ at the same time, tell me, what city has enough law enforcement to arrest EVERY MJ user/supporter in the city that came together...What message would that send...The sheeple arent bending over?!?
5 / 5 (1) May 31, 2009
I have never used drugs other than alcohol accept when prescribed by a physician. Coming down from the stuff that they fed me was far more unsettling than coming off of alcohol and I drank to excess for many years. I have been off of alcohol for over twenty years and work with alkies and OTHER addicts daily. Tobacco and alcohol are just as likely, if not more so, to create addiction as almost any other but as long as the government can make money from it or it's consequences, they will remain legal and taxed. Prohibition of anything will create the psychological demand for it. Since the government has become a primarily fund raising entity, that will dictate what the laws will reflect.
not rated yet May 31, 2009
SiLiass-I agree with you whole heartedly, but alas, those few of our brothers and sisters who did get arrested would have to spend something like, what, 5 whole days in jail if we did that...and without smoke :(
Although that could make a good revolution starting place....attack back while being attacked by the supposed "law enforcement" folks who do nothing more than ruin peoples lives for things that in the grand scheme of things mean absolutely dick...
I like your thinking though :)

marijuana has no kind of come down like pharmaceutical drugs. You are comparing something natural to something unnatural. Our own bodies, YES, our own bodies, make the exact same substance found in marijuana (that being THC). In fact, each one of us in the world has skin that creates THC naturally (but only along the lines of something like .005% per cell or something like that. My point being, can something our body makes naturally, and something that grows naturally as well, be even close to as bad as something that some schmuck in a lab made? There are in fact direct correlations, such as smoking a doobie to rid yourself of a headache, or popping a few aspirin. I'll tell you what, a doobie aint gonna give you a heart attack (aspirins heart helping ways ONLY work on those with already existing heart problems).
5 / 5 (3) May 31, 2009
I know it's been said a million times before... but...

You can get highly addictive cigarettes *legally* that will give you 20 kinds of cancer, and eventually kill you slowly and painfully - or quickly from a heart attack, or some other horrible illness.

You can get highly addictive alcohol *legally* that will give you cirrhosis, kill brain cells, and make you violent and a potential threat to society.

Marijuana, which has been shown to have an anti-cancer effect (both anti-tumor and anti-nausea, thereby increasing duration and quality of life for cancer patients), is nowhere near as addictive as alcohol or tobacco, is *illegal*?

Who makes this stuff up, and why do they want us sick or dead?
5 / 5 (1) Jun 02, 2009
Oh why they want us sick you ask? That's an easy one... See, if you are sick, then you have to buy the drugs that THEY make. You know, those drugs that ARE highly addictive. Pharmaseudical companies are pure evil... I know, I worked for one of them lol.

They are the ones producing and rushing these supposedly beneficial substances to market long before and real research is done on them. Small wonder that most anti-depressents carry a risk of suicide. But hey... worth the risk right? Especially for your 3 or 4 year old children. Cause we all know you have to start em young.

Pharmasuedicals learned that lesson from big tobacco.

Doesn't that just make you want to support your local A.N.U.S.?
5 / 5 (1) Jun 02, 2009
A.N.U.S. says - and true justice for all :D

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