[I.M. Boggled]

Because cannabis is psychoactive in nature, questions naturally arise as to its possible negative effects on the human brain or brain chemistry.


Analysis of Studies Finds Little Effect From Long-Term Use
By Sid Kirchheimer

July 1, 2003 -- Long-term and even daily marijuana use doesn't appear to cause permanent brain damage, adding to evidence that it can be a safe and effective treatment for a wide range of diseases, say researchers.

The researchers found only a "very small" impairment in memory and learning among long-term marijuana users. Otherwise, scores on thinking tests were similar to those who don't smoke marijuana, according to a new analysis of 15 previous studies.

In those studies, some 700 regular marijuana users were compared with 484 non-users on various aspects of brain function -- including reaction time, language and motor skills, reasoning ability, memory, and the ability to learn new information.

Surprising Finding

"We were somewhat surprised by our finding, especially since there's been a controversy for some years on whether long-term cannabis use causes brain damage," says lead researcher and psychiatrist Igor Grant, MD.

"I suppose we expected to see some differences in people who were heavy users, but in fact the differences were very minimal."

The marijuana users in those 15 studies -- which lasted between three months to more than 13 years -- had smoked marijuana several times a week or month or daily. Still, researchers say impairments were less than what is typically found from using alcohol or other drugs.

"All study participants were adults," says Grant, professor of psychiatry and director of the Center for Medicinal Cannabis Research Center at the University of California, San Diego School of Medicine.

"However, there might be a different set of circumstances to a 12-year-old whose nervous system is still developing."
10 States OK Marijuana Use

Grant's analysis, published in the July issue of the Journal of the International Neuropsychological Society, comes as many states consider laws allowing marijuana to be used to treat certain medical conditions.
Earlier this year, Maryland became the 10th state to allow marijuana use to relieve pain and other symptoms of AIDS, multiple sclerosis, cancer, glaucoma, and other conditions -- joining Alaska, Arizona, California, Colorado, Hawaii, Maine, Nevada, Oregon, and Washington.

Medicinal marijuana is available by prescription in the Netherlands and a new marijuana drug is expected to be released in Great Britain later this year. In the U.S. and elsewhere, Marinol, a drug that is a synthetic form of marijuana and contains its active ingredient, THC, is available by prescription to treat loss of appetite associated with weight loss in AIDS patients.

Grant says he did the analysis to help determine long-term toxicity from long-term and frequent marijuana use. His center is currently conducting 11 studies to determine its safety and efficacy in treating several diseases.

"This finding enables us to see a marginal level of safety, if those studies prove that cannabis can be effective," Grant tells WebMD. "If we barely find this effect in long-term heavy users, then we are unlikely to see deleterious side effects in individuals who receive cannabis for a short time in a medical setting, which would be safer than what is practiced by street users."

Grant's findings come as no surprise to Tod Mikuriya, MD, former director of non-classified marijuana research for the National Institute of Mental Health Center for Narcotics and Drug Abuse Studies and author of The Marijuana Medical Handbook: A Guide to Therapeutic Use. He is currently president of the California Cannabis Medical Group, which has treated some 20,000 patients with medicinal marijuana and Marinol.

'Highly Effective Medicine'

"I just re-published a paper of the first survey for marijuana toxicity done in 1863 by the British government in India that was the most exhaustive medical study of its time in regards to possible difficulties and toxicity of cannabis. And it reached the same conclusion as Grant," Mikuriya tells WebMD.

"This is merely confirming what was known over 100 years ago, as well as what was learned by various government findings doing similar research -- marijuana is not toxic, but it is a highly effective medicine."

In fact, marijuana was available as a medicinal treatment in the U.S. until the 1930s.

Lester Grinspoon, MD, a retired Harvard Medical School psychiatrist who studied medicinal marijuana use since the 1960s and wrote two books on the topic, says that while Grant's finding provides more evidence on its safety, "it's nothing that those of us who have been studying this haven't known for a very long time.

"Marijuana is a remarkably safe and non-toxic drug that can effectively treat about 30 different conditions," he tells WebMD. "I predict it will become the aspirin of the 21st century, as more people recognize this."

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SOURCES: The Journal of the International Neuropsychological Society, July 2003. Igor Grant, MD, professor of psychiatry, University of California, San Diego School of Medicine; director, UCSD Center for Medicinal Cannabis Research Center. Tod Mikuriya, MD, president, the California Cannabis Research Medical Group, Oakland; former director of non-classified marijuana research, the National Institute of Mental Health Center for Narcotics and Drug Abuse Studies. Lester Grinspoon, MD, professor emeritus of psychiatry, Harvard Medical School, Boston; author, Marijuana: The Forbidden Medicine and Marihuana Reconsidered.

[guineapig]

the drawback to heavy cannabis use is tolerence.....

[aborted]

Now that's just something i've known since the first time I lighted a spliff. People just won't accept the greatness in the sacred plant...:(

[HairlessCaveApe]

Yea Brudda! Mariwanner makes ya smarta! Yea . I think we were suposed to smoke it. I think it was a natural part of our phisical and spiritual evolution somewhat simular to the way Shrooms entered into our systems. Deeply spiritual this Herb. Phisicaly healing and soothing to the soul. A true Gift of God! :smile:

[Harry Gypsna]

think this is true, but I would have to say that there is a definate possibility of truth in the theiry of it wiring ur mind a bit different if you smoke a lot as a kid and ur brain is still developing.... in fact I seem to fit all the charcteristics that they describe as being a reult of heavy adolescant use.... lol....
whie I wouldwish for responsible adults to have the freedm to choose, I dont think kids should be smoking it at all... I used to think different not 2 years ago but recently ive started thinking really kids shouldnt be smoking it.... at least not all the time anyway.....if id stuck to weekends only when i was 12-15 then maybe id have finsihed shcool, you never know.....
I have an open enough mind to acceopt that there could be a chance of some harm coming to certain groups of people(kids/mentally il or susceptible to mental illness) from smoking dope....i wont just blindly say weeds harmless thats that....because to do so would be the same as the morons who say its evil and thats that.....
Its just a pity that most of the research done is either to find a way to make money out of it, or started with a result in mind, ie dope is bad.... we need more completely 100% imopartial researcg to ever know completely 1 way or the other