Harvard University Study: Cognition unaffected by pot use.

in General Discussion edited January 2014
From: <a href="http://www.news.harvard.edu/gazette/2001/10.18/03-marijuana.html"; target="_blank">http://www.news.harvard.edu/gazette/2001/10.18/03-marijuana.html</a>;



Cognition unaffected by pot use:

But other studies suggest marijuana smokers are not a happy lot

By William J. Cromie

Gazette Staff

A new study of cognitive changes caused by heavy marijuana use has found no lasting effects 28 days after quitting. Following a month of abstinence, men and women who smoked pot at least 5,000 times in their lives performed just as well on psychological tests as people who used pot sparingly or not at all, according to a report in the latest issue of the Archives of General Psychiatry.

That's the good news. The bad news, not included in the study, is that most heavy users admit that pot has had a negative effect on their physical and mental health as well their functioning on the job and socially.

"If there's one thing I've learned from studying marijuana for more than a decade, it's that proponents and opponents of the drug will put opposite spins on these findings," says Harrison Pope, a Harvard professor of psychiatry and leader of the research. "One day I'll get a letter that will say, 'We are shocked that you are so irresponsible as to publish a report that claims marijuana is almost harmless. That's a terrible disservice to our children.' The next day, I'll get a letter complaining that I'm 'irresponsible for implying there's something wrong with smoking marijuana. You have set back the legalization (of marijuana) movement by 20 years.'

"As a scientist, I'm struck by how passionately people hold opinions in both directions no matter what the evidence says. The other striking thing is how little we actually know about the effects of a drug that has been smoked for thousands of years and been studied for decades."

Withdrawal produces impairment

That shortage of knowledge motivated Pope and his colleagues at McLean Hospital, a Harvard-affiliated psychiatric facility in Belmont, to investigate the drug's long-term cognitive effects. They recruited 180 people, 63 of them heavy users who currently smoked pot daily, 45 former heavy users, and 72 who had used the drug no more than 50 times in their lives. Heavy use was defined as smoking pot at least 5,000 times. The subjects ranged in age from 30 to 55 years. Most of them were males because studies indicate that women are less likely to become heavy marijuana users.

All took batteries of intelligence, attention, learning, and memory tests on days zero, one, seven, and 28 after quitting the drug. (Daily urine samples confirmed whether or not they had stopped.) On days zero, one and seven, current heavy smokers scored significantly lower than the other groups on memory tests.

"By day 28, however, there were no significant differences among the groups on any of 10 different tests, and no significant association between cumulative lifetime marijuana use and test scores," Pope says. In other words, the researchers conclude that heavy marijuana use produces no irreversible mental deficits.

The investigators cannot say for sure why pot smokers remain impaired for days or weeks after giving up the drug. One possibility is that they retain substantial amounts of a compound known as THC, the active ingredient of marijuana, in their systems. THC dissolves in body fat, then slowly percolates into the blood and brain over days and weeks after a joint is smoked.

Another explanation blames a withdrawal effect, similar but not as pronounced as the agitation, irritability, sleeping problems, and appetite loss suffered by users of heroin or alcohol. Such symptoms impair attention and memory.

"Some of the deficits we saw were as bad, or even worse on day seven as on day one," Pope notes. "This suggests that withdrawal, rather than a residue of drug in the brain, accounts for the bulk of lingering impairments." A residue effect should decrease from day one to seven after quitting, but withdrawal problems would increase before they decrease.

Pot smokers who believe they are back to normal sometimes show detectable impairments on various tests. "That's a cause for concern," Pope points out. "You don't want to try landing a 747, driving a bus or train, or taking a calculus test a week after heavy marijuana use even if you feel normal."

Unsatisfied lives

Although researchers found no irreversible cognitive defects from a lifetime of marijuana consumption, pot users are not a happy lot. In a separate study, most heavy users admitted that the drug has a negative impact on all aspects of their lives from job performance and physical health to mental well-being and satisfactory socializing.

Heavy smokers also have substantially smaller incomes and lower levels of education than nonusers or light users, despite the fact that the education and income levels of their families are the same. However, there's no way to determine if marijuana is the cause or if these people naturally have less ambition.

"It's a chicken-and-egg situation," Pope admits. "Probably the direction of causality goes both ways. In all likelihood, people who become frequent users are somewhat different at the outset; they may have lower cognitive abilities or less motivation. Once they start using the drug regularly, these differences become wider."

Asked if his conclusions would lead him to make any recommendations for or against legalizing marijuana, Pope answered, "No, because so many other political and social factors are involved." He noted that alcohol, which is sold legally, causes cognitive deficits in long-term heavy users that do not disappear after 28 days and may be cumulative. However, he adds, "such toxicity is only one factor in the decision."

A number of investigations have linked marijuana to an increased risk of lung cancer. A recent Harvard study concluded that a middle-aged person's chance of having a heart attack increases nearly five times during the first hour after smoking pot. That's especially meaningful for baby boomers who developed the habit in their teens and 20s and continue to use the drug in their 30s, 40s, and 50s. Other researchers have associated pot with impaired disease resistance and adverse effects on fetuses when mothers smoke the drug during pregnancy.

On the other hand, many claims exist that marijuana eases the nausea produced by cancer drugs and relives the pain of diseases such as AIDS, severe arthritis, and glaucoma. Such claims led Canada recently to legalize its medical use.

Pope raises a caveat: "Is it better than other treatments for the same conditions? Given the association with lung cancer and other ills, does it provide more benefit than risk?"

Pro-pot people argue that, even if marijuana is only equal in efficacy to prescription and over-the-counter drugs, it's much cheaper. "After all, it's only a weed," Pope points out.<hr></blockquote>

Makes for an interesting read. This will certainly be used in the battle to legalize marijuana. I'm still sort of on the fence as to whether smoking actually affects people in a manner that affects cognitive skills. I've seen evidence both for and against it. What do you guys think?



  • Reply 1 of 29
    powerdocpowerdoc Posts: 8,123member
    The good new is that one month after stopping the pot things will return to normal.

    The article say also, that smoking pot lower your intelectual faculties, it's a cause of car accident too (like alcoohol).

    The pot can be the first step for the use of more dangerous drug, the pot should not be recommanded. I should had also, that people smoke cigarettes has better chances to have try Marijuana than people who don't smoke.

    The legalisation of Marijuana can have a paradoxal effect, marijuana is popular also because it's forbidden, it's a way to transgress laws, if it is permitted there is a risk that some people may try harder stuff.

    However, smoking marijuana is not pure evil, be totally drunk is more dangerous for the personn concerned and for the people around ...but i don't think it's a reason to alloud it.

    I have 2 girls, i don't want them to smoke, cigarettes or marijuana, i don't want they take drugs or be drunk and/or alcooholic. It's not very original but it's my point me and my wife.
  • Reply 2 of 29
    powerdocpowerdoc Posts: 8,123member

    The title of the Harvard gazette should be : Cognition unaffected one month after the stop of pot use.

    It's quite evident that heavy pot users doens't seem to be intellectually brillant. The good new is that after stopping it , things will be returning to normal.
  • Reply 3 of 29
    bellebelle Posts: 1,574member
    Now if they could just find the component part that makes users ignorant, self-righteous, incredibly boring assholes, we'd be laughing.
  • Reply 4 of 29
    ybotybot Posts: 329member
    [quote]Originally posted by Belle:

    <strong>Now if they could just find the component part that makes users ignorant, self-righteous, incredibly boring assholes, we'd be laughing. </strong><hr></blockquote>

    Talking about me or Powerdoc there?

    <img src="confused.gif" border="0">
  • Reply 5 of 29
    bellebelle Posts: 1,574member
    [quote]Originally posted by Ybot:

    <strong>Talking about me or Powerdoc there?

    :confused: </strong><hr></blockquote>


    Just my view of pot users in general, and how I know I acted when I used to use it.
  • Reply 6 of 29
    pfflampfflam Posts: 5,053member
    Pot should be legal.

    Though habitual use does make people tend to be boring assholes . . . its relativly harmless. this supposed link between it and harder drugs is no kind of reason to legislate. It may be that a personality type that would want to experimant with marijuana may also be the type to try other things . . .

    Anyway, the largest benefit from legalization would be that the incredibly well funded industry of illegal drugs would suddenly dry up, and criminals would have no more source of income.

    Besides its my body and I have a right to smoke it if I want to . . .even tough I don't.

    Its negative impact on society is negligible: and clearly alchohol has more detrimental side effects. And no, alchohol should not be illegal!!!!!
  • Reply 7 of 29
    bellebelle Posts: 1,574member
    [quote]Originally posted by pfflam:

    <strong>Pot should be legal.

    Though habitual use does make people tend to be boring assholes . . . its relativly harmless.</strong><hr></blockquote>

    True. I have an idea - legalize pot, and make being a boring asshole a criminal offense.

    Come to think of it, I can see benefits of this policy way beyond the legalizing pot debate...
  • Reply 8 of 29
    brussellbrussell Posts: 9,812member
    [quote]Originally posted by Belle:

    <strong>make being a boring asshole a criminal offense.</strong><hr></blockquote>

    Hmm, what implications would this have for the legal status of AppleOutsider?
  • Reply 9 of 29
    bellebelle Posts: 1,574member
    [quote]Originally posted by BRussell:

    <strong>Hmm, what implications would this have for the legal status of AppleOutsider?</strong><hr></blockquote>

  • Reply 10 of 29
    groveratgroverat Posts: 10,872member
    BRussell, I'm afraid that you would have already been executed.
  • Reply 11 of 29
    I find it amusing that one set of liberals is trying to take down the tobacco industry and a different set of liberals is trying to create a new one.
  • Reply 12 of 29
    marcukmarcuk Posts: 4,442member
    My best friend smokes Pot heavily, and I don't smoke it at all, and to be honest, It has turned him into a extremely boring asshole, so much so that I havn't spoken to him for 9 months.

    But legalising it doesn't make the pushers go away. Insted of pushing a kid pot, they'll make their money by pushing them something much harder.

    I'd agree that Pot is not dangerous, and if people are stupid enough to give someone a big wedge to make themselves a boring ass, then thats their problem, but I doubt that in the absence of Pot they'dd suddenly be reformed. More likely to find something else to get their fix.
  • Reply 13 of 29
    cdhostagecdhostage Posts: 1,038member
    If smoking pot is less dangerous to the smoker and the people around him than drinking beer, then I am all for it. The government has the right to police substances that cause proven damage to people and pose a risk to people around those who use them. If the stuff causes no more than a general good feeling and a sense of comraderie, the ogvernment has no right to police it.
  • Reply 14 of 29
    buonrottobuonrotto Posts: 6,368member
    Belle: HA! And they raid the 7-11 for muchies all the time!

    Scott H: Dammit, you're right. Like the pro-death penalty/anti-abortion stance, so much of politics is hypocrisy. Just goes to show that politicians and political groupies have no sense and why we should avoid following the crowd on this junk.

    Personally, I'm for legalizing pot for medical use (regulation) and I have no desire to make tobacco illegal, perhaps just regulated too. Now about all that telecom deregulation...
  • Reply 15 of 29
    I've had friends tell me that smoking pot heavily caused them to lose memories and have no ability to think. Most of them have stopped, for whatever reason.

    The reason why this Harvard survey tries to cast pot in at least a somewhat acceptable light is because Harvard is full of ugly potheads!
  • Reply 16 of 29
    brussellbrussell Posts: 9,812member
    [quote]Originally posted by Scott H.:

    <strong>I find it amusing that one set of liberals is trying to take down the tobacco industry and a different set of liberals is trying to create a new one.</strong><hr></blockquote>

    There are at least as many on the right who talk seriously about legalizing drugs.
  • Reply 17 of 29
    [quote]I've had friends tell me that smoking pot heavily caused them to lose memories and have no ability to think. Most of them have stopped, for whatever reason.<hr></blockquote>

    I have a friend who had memory problems from heavy smoking. He stopped due to panic reactions, as did I. My friend felt a bit a loss over quitting, because he liked doing it, did it a lot, and probably associated it with friends. I didn't find anything much good in it in the first place.
  • Reply 18 of 29
    steve666steve666 Posts: 2,600member
    I'd rather be around a boring asshole than a violent drunk. Pot should be legal for anyone 21 and over. Period.........................................
  • Reply 19 of 29
    Man...from reading this thread I can't help but wonder if we're talking about the same drug. This place really is turning into the GOP Online isn't it? :cool:

    Anyway, that study pretty much reiterated what I think everyone already knew. There's no big surprises about pot anymore. Long story short: it's relatively harmless, and it gives you the munchies. All other factors (whether it makes you a boring asshole or not, for example) has a lot to do with who's smoking, and how good your stash is! <img src="graemlins/smokin.gif" border="0" alt="[Chilling]" />
  • Reply 20 of 29
    Hell, look at what Pot did to Bill Clinton. And he didn't even inhale. <img src="graemlins/smokin.gif" border="0" alt="[Chilling]" />
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