|Drug's Effect on Brain Is Extensive, Study Finds|
Posted by FoM on March 05, 2001 at 21:50:48 PT|
By Sandra Blakeslee
Source: New York Times
Heavy users of methamphetamine — a highly addictive stimulant that can be made at home in the kitchen sink — are doing more damage to their brains than scientists had thought, according to the first study that looked inside addicts' brains nearly a year after they stopped using the drug.
At least a quarter of a class of molecules that help people feel pleasure and reward were knocked out by methamphetamine, the study found.
Some of the addicts' brains resembled those of people with early and mild Parkinson's disease. But the biggest surprise is that another brain region responsible for spatial perception and sensation, which has never before been linked to methamphetamine abuse, was hyperactive and showed signs of scarring.
On tests of memory, attention and movement, the methamphetamine addicts did worse compared with people who do not use drugs, the study reported. The researchers said it was too soon to know if people who stopped taking the drug for more than a year would recover lost brain function.
The study was led by Dr. Nora Volkow, associate director for life sciences at the Brookhaven Haven National Laboratory in Upton, N.Y., and appears in the March issue of The American Journal of Psychiatry.
This is the first study to show directly that brain damage caused by methamphetamine produces deficits in learning and memory, said Dr. Alan Leshner, director of the National Institute on Drug Abuse, which helped finance the new research. Use of the drug has reached epidemic proportions in Hawaii, California and parts of the Midwest, he said. Made in clandestine laboratories from cheap ingredients, it is known as speed, meth, chalk, ice, crystal and glass. The drug can be smoked, snorted, injected or taken by mouth. A $5 dose produces euphoria and increases energy for hours, whereas a cocaine high may last only half an hour.
It's not clear why some people choose cocaine over methamphetamine or vice versa, Dr. Volkow said. Estimates are that five million American have experienced methamphetamine and maybe one million to two million are regular users. "It's a bigger problem that heroin," she said.
Over the years, the addicts in the study had taken pounds of methamphetamine, an amount that is enough to kill laboratory animals, Dr. Volkow said. "Actually, I am stunned these people are not dead."
In the study, Dr. Volkow used an imaging technique called positron emission tomography to measure dopamine levels in the brains of 15 recovering addicts and 18 healthy volunteers. Dopamine is a brain chemical that regulates movement, attention, pleasure and motivation. When the dopamine system goes seriously awry, she said, people lose their excitement for life and can no longer move their limbs. Their brains were then imaged a second time to measure how different parts of their brains metabolize energy.
The addicts smoked or injected methamphetamine all day for several years, Dr. Volkow said. They had started out as occasional users but over time the drug hijacked their natural dopamine systems. Two weeks after the brain images were taken, the addicts and the volunteers were brought back to the laboratory and asked to do tasks like walking as fast as possible in a straight line, rapidly inserting pegs into small holes angled in different directions, matching numbers with symbols, recalling lists of unrelated words and carrying out other tests that measure brain acuity.
On average, dopamine was 24 percent lower in addicts than in normal volunteers, Dr. Volkow said. They were clumsier at putting pegs in the holes and had difficulty remembering words. Half the addicts said they felt their brains were not working as well as they used to.
But the study's biggest surprise was that the addicts' parietal lobes, the parts of the brain used for feeling sensation and recognizing where the body is in space, were metabolically overactive, Dr. Volkow said. Other studies showed that metabolism increased when the brain suffered traumatic injury or got high doses of radiation, she said. It is the equivalent of an inflammation or scarring response.
The loss of dopamine is also worrisome, Dr. Volkow said. Three drug abusers had dopamine levels that fell within the range seen in patients with low-severity Parkinson's disease. Because dopamine levels fall naturally with age, it's unclear what will happen to these people 30 years from now.
"We don't know if they will recover dopamine function or not," she said.
Five of the fifteen addicts have not relapsed and are being re-examined with brain imaging to see if their dopamine levels rebound. All smoke heavily, and it may be that nicotine protects their brains from being more severely damaged, she said. If that is the case, treatments for methamphetamine abuse might include nicotine patches and drugs to enhance dopamine function along with behavioral therapy.
Related Articles & Web Site:
American Journal of Psychiatry
The Brain: The Origins of Dependence
Seeing Drugs as a Choice or as a Brain Anomaly
|Comment #11 posted by FiveD on March 07, 2001 at 03:21:26 PT|
|I dont mean to suggest that actual research was not done by honest,well schooled people...BUT|
May I respectfully suggest,that such "news" stories,are little more than chintzy,
This,,and many other such releases are what I will proudly call "CHOW".....
It's rather spooky to realize,that many such stories/articles,are not the seemingly
Properly written "news" propaganda,is invisible to almost everyone.Observer is
So...for the usual attempt to summarize my typicly verbose,cacographic katzenjammer,
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Comment #10 posted by Dan B on March 06, 2001 at 14:52:51 PT:|
|Here's an abstract that may be useful to those arguing against prohibitionists who say that there is no accepted medical use of marijuana. In short, there is:|
Marijuana as antiemetic medicine: a survey of oncologists' experiences and attitudes.
Doblin RE, Kleiman MA
Kennedy School of Government, Cambridge, MA 02138.
A random-sample, anonymous survey of the members of the American Society of Clinical Oncology (ASCO) was conducted in spring 1990 measuring the attitudes and experiences of American oncologists concerning the antiemetic use of marijuana in cancer chemotherapy patients. The survey was mailed to about one third (N = 2,430) of all United States-based ASCO members and yielded a response rate of 43% (1,035). More than 44% of the respondents report recommending the (illegal) use of marijuana for the control of emesis to at least one cancer chemotherapy patient. Almost one half (48%) would prescribe marijuana to some of their patients if it were legal. As a group, respondents considered smoked marijuana to be somewhat more effective than the legally available oral synthetic dronabinol ([THC] Marinol; Unimed, Somerville, NJ) and roughly as safe. Of the respondents who expressed an opinion, a majority (54%) thought marijuana should be available by prescription. These results bear on the question of whether marijuana has a "currently accepted medical use," at issue in an ongoing administrative and legal dispute concerning whether marijuana in smoked form should be available by prescription along with synthetic THC in oral form. This survey demonstrates that oncologists' experience with the medical use of marijuana is more extensive, and their opinions of it are more favorable, than the regulatory authorities appear to have believed.
Just a side-note: I've been looking at all articles related to cannabis and cancer. It appears that it is associated with lung cancer, particularly that of the upper respiratory tract, but mainly in chronic habitual long-term users. The studies I have seen (bear in mind I have only seen the abstracts) seem problematic in that almost all of them use subjects who habitually smoke both tobacco and cannabis, some of whom also drink alcohol. It seems unclear, then, whether cannabis causes cancers, or merely exacerbates cancers caused by other agents. Some molecular-level studies suggest that cannabis smoke causes precancerous changes in cells, so the idea that smoked cannabis causes cancers is not outside the realm of possibility. What I have not determined is the rate at which these cancers may develop, although at least one study said that it was dose-specific, which makes sense. There does seem to be a consensus that vaporizers can and do limit the amount of carcinogenic material introduced to the body due to fewer carcinogenic chemicals associated with burnt organic matter.
My conclusion thus far is that my own infrequent, sporadic use of cannabis is not likely to result in cancer, even in the long term, and that I can limit future carcinogenic effects by using a vaporizer or some other method of introducing cannabis into my system, should I choose to do so.
I hope this is useful to someone. If you want to check out the publication abstracts for many good articles on the subject, click one of the links provided by Dr. Ethan Russo or myself and use the search function at the top of the page to find the subject about which you are most interested. Articles are listed by date, most recent first.
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Comment #9 posted by Ethan Russo, MD on March 06, 2001 at 11:51:30 PT:|
|Immunocompromised patients should heat cannabis in an oven at 150 degrees Celsius for 5 minutes to reduce risk before eating or smoking or vaporizing.|
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Comment #8 posted by Dan B on March 06, 2001 at 11:41:20 PT:|
|I've been checking out PubMed, and there are quite a lot of articles on cannabis and lung function/lung cancer. Of particular interest to me were these two 1986 articles; I'll be checking out more when I have more time (I'm taking a break at work right now):|
1986 study by Hollister shows that a cannabis connection to emphysema and lung cancer has not been shown (but it has been 15 years since this study was published).
1986 study shows that fungi associated with cannabis may cause problems for lung cancer patients using it as an adjuct to chemotherapy, but does not focus on the harm associated with cannabis itself.
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Comment #7 posted by Ethan Russo, MD on March 06, 2001 at 11:13:54 PT:|
|Dan, check out PubMed and decide for yourself:|
and plug in search terms such as: cannabis, marijuana, "lung cancer", pulmonary, Tashkin
You will get a lot, believe me. The important lessons are that smoking cannabis chronically carries some risks. Most medical users are not apt to run into serious problems. Risk reduction (vaporizers, potent cultivars, etc.) should be applied when possible. Stamp out paraphernalia laws!
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Comment #6 posted by Dan B on March 06, 2001 at 09:40:11 PT:|
|I am curious as to the evidence concerning cannabis use and lung cancer. Is it that we cannot prove it does not cause lung cancer, or is it that we have proven that it, in fact, has caused lung cancer in some users? If the latter, I wonder if the ratio of smokers to lung cancer patients is comparable to that for tobacco, for example.|
I appreciate your insight, comments, and links. I also appreciate bcg's comments. Many thanks to both of you.
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Comment #5 posted by Ethan Russo, MD on March 06, 2001 at 08:06:35 PT:|
|We have no neuropsychological evidence that Ritalin or amphetamines cause cognitive damage in the longterm when taken properly in appropriate doses. As with any drug, there is use, and there is abuse. The effects are distinct.|
[ Post Comment ]
Comment #4 posted by Bob on March 06, 2001 at 06:58:56 PT:|
| To most people the idea that homemade speed causes brain damage is easy to believe, but what about Ritalin, Dexedrine, and Aderol? These are only slightly different from the meth on the street, yet they are prescribed to children who already have problems related to dopamine. Is this short term fix for ADD children actually worsening their problems in the long run? This article would seem to indirectly suggest that.|
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Comment #3 posted by Ethan Russo, MD on March 06, 2001 at 06:29:12 PT:|
|There are few simple answers here. |
Firstly, I have no doubt that prolonged methamphetamine abuse has a deleterious effect on a person's functioning. I do not recommend such abuse.
I have not read this article, but the data sound compelling. A couple of disclaimers are necessary. One must always be aware that NIDA funding may indicate a certain orientation. The mission of this agency is to demonstrate the ravages of drug usage. Sometimes biases prevail. PET scanning is a research tool, and may be subject to interpretation. Often the images are presented as photos showing hypo or hyper-metabolism in certain areas. A movie over time would be a more accurate portrayal. Thus, Pet scans are static representations of a dynamic process. PET is not reimburseable by private insurance for most indications, and is often not admissible in court.
We cannot say that cannabis smoking has never caused lung cancer, but it does not produce emphysema:
Any problems of clinical or "recreational" cannabis in this regard may be totally eliminated by alternative delivery systems: oral, sublingual tincture, vaporization. We should explore these.
A tremendous amount of research has been funded by NIDA over the years in attempts to demonstrate "brain rot" secondary to cannabis. Most were poorly done, and unsubstantiated. These have been refuted:
but the antis only remember the old propaganda.
Many studies have examined neuropsychological effects of cannabis. Results have been minimal and mild. See work of Fried on developmental aspect of children born to cannabis-using mothers:
but refuted by data from Jamaican Rastafarian mothers by Dreher:
Nadia Solowij has probably done the best work claiming neuropsychological changes in chronic cannabis smokers, but reported effects are very subtle:
Studies by Lyketsos are encouraging that little or no change is evident:
There is an incredible body of evidence demonstating the neuroprotective and antioxidant effects of cannabis components, especially THC and CBD exceeding vitamins C and E:
All the chronic use studies from Jamaica, Costa Rica are encouraging that users do not differ from controls in mental functioning.
I believe that cannabis is an incredibly useful phytomedicinal with a fabulous safety margin, particularly when employed with alternative delivery systems. We will be addressing many of these issues in the Journal of Cannabis Therapeutics.
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Comment #2 posted by bcg on March 06, 2001 at 05:54:11 PT:|
|In my research as a graduate student (I study cocaine abuse) I have come across some literature indicating that cannabinoids (anandamide is like prostaglandin in origin) act at some prostaglandin receptors. These are the "mediators of inflammation" Cannabinoid action at these receptors may be why there has never been a link between people who use cannabis (and only cannabis - not tobacco + cannabis) and emphysema or cancers. NIDA would be all over a study that showed such a thing, but the evidence just doesn't bear that out.|
This is an avenue I may pursue after I get my PhD and get the heck out of drug abuse research - Cannabinoids and inflammation via the prostaglandin receptor
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Comment #1 posted by Dan B on March 05, 2001 at 22:48:27 PT:|
|All smoke heavily, and it may be that nicotine protects their brains from being more severely damaged, she said. If that is the case, treatments for methamphetamine abuse might include nicotine patches and drugs to enhance dopamine function along with behavioral therapy. |
Interesting. I had a friend in the psychology department at Texas Tech who was studying the effects of nicotine on learning. What he found was that nicotine enhances memory and other skills associated with greater capacity for learning. Of course, there are also the negative health risks that keep many people from using cigarettes for this express purpose.
I don't recall him telling me that smoked tobacco protects the brain, but if such is the case then it stands to reason that that cannabis--an herb that has been shown to shrink certain cancerous tumors--can be used as a protector against cancers even if smoked!
I believe this is why cannabis has never been linked with lung cancers, as has tobacco. The carcinogens found in the smoke may be cancelled out, so to speak, by the postive cancer-fighting cannabinoids also found in that smoke. And if smoked cannabis actually protects the smoker against lung cancers, what other ailments might it also protect against, aside from the most common ones we already know about?
I would be greatly interested in any insights Dr. Ethan Russo in particular (but everyone else as well) might have on this subject.
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