+ Brain Shrinkage Seen With Marijuana Use

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this is Neomi Heroux’s article in Health News:

Many people believe that marijuana is relatively harmless and should be legalized. There are just as many who believe that its use is the start of all addictions and can only lead to self destruction. The attitude of both sides of the controversy probably has as much to do with personal morals and religious beliefs as with medical truth.

Reports suggest that long-term marijuana use is associated with adverse health consequences, but there have been relatively few studies that can confirm any disease directly associated with marijuana use. Researchers admit that excess use of almost any substance can contribute to disease and poor health in an individual. A substance that affects the brain and nerves will have more effect with increased usage.

New evidence indicates that long term heavy use of marijuana can cause abnormalities in the brain. These abnormalities are actual brain injuries leading to memory loss, difficulty in learning, paranoia, delusions and bizarre social behaviors. The new evidence was the result of research by the ORYGEN Research Centre and the Neuropsychiatry Centre at the University Of Melbourne, Australia. Lead researcher Murat Yucel, says the new evidence plays an important role in understanding the effects of marijuana and its impact on brain functioning. Yucel said. “The study is the first to show that long-term cannabis use can adversely affect all users, not just those in the high risk categories such as the young or those susceptible to mental illness, as previously thought,”

The research team did high resolution MRIs on 15 men who smoked more than five joints a day for more than 10 years. The scans were compared with those of 16 men who did not use marijuana. All of the men took verbal memory tests and had examinations for psychiatric disorders. According to Yucel the more marijuana was used the more the individuals were likely to have reduced brain size in the parts of the brain that control emotion, memory, fear and aggression. Heavy users were also much more likely to develop psychotic disorders. According to Yucel the study challenges the perception that cannabis has limited or no harmful effects on the brain and behavior. The study does not link modest use to neurotoxic effects, only heavy daily use. The study group was not frequent users of other illicit drugs.

This study is not likely to end the controversy surrounding marijuana use. The researchers said that the study did not prove whether it was the marijuana or other factors that triggered the brain differences, even though it suggested that the marijuana use was the cause. The size of the hippocampus and the amygdale, the two portions of the brain that were studied may have been smaller in the study individuals to begin with and may have contributed to the heavy usage. Meanwhile in May scientists at New York University tested a group of 17- to 30-year-old cannibis smokers who used the drug twice a week for a year. There was no difference between the users and a group of non-users.

Supporters of legal sales of marijuana did not believe the study was very useful because it covered a very small group of individuals who were long term heavy users of marijuana, and the majority of users are moderate occasional users. The heavy use of alcohol and tobacco is far more serious than recreational use of marijuana according to a spokesman.

rom a parent’s point of view the important question is whether the brain differences were the result of the long term usage, or the age at which they began using the drug. Scott Swartzwelder, professor of psychiatry and behavioral sciences at Duke University, whose research focuses on substance abuse and the adolescent brain, said that it is too early for parents to conclude that pot deteriorates the brain. The study used a very limited set of data, the study was tiny, and looked for extreme behavior. “I’m not sure how relevant it is to the general public.” says Swartzwelder.

The researchers noted that the size of the group is an issue, but finding subjects who used a lot of pot but didn’t do other drugs, or have medical or psychological issues was difficult. The continuing use of cannabis within the general population demands a clear scientifically correct study that both sides of the usage controversy can accept.

this is Neomi Heroux’s article in Health News on 6/9/08.  www.healthnews.com

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