Pubdate: The, 14 Mar 2006
Source: Dominican Today (Dominican Republic)
Copyright: 2006 Dominican Today
Bookmark: (Cannabis)


Athens - People who regularly smoke marijuana may  find their 
memories growing hazy over time, a study  published Monday suggests.

In a study of long-term and shorter-term marijuana  users, 
researchers in Greece found that both groups  performed more poorly 
on tests of memory, attention and  other cognitive abilities than a 
comparison group who'd  only occasionally used the drug.

Long-term users - who'd smoked four or more joints per  week for at 
least 10 years - showed the greatest  deficits.

The findings, published in the journal Neurology, add  to the 
conflicting body of research on the effects of  marijuana on the 
brain. While many studies have  suggested that long-time pot smoking 
dulls memory,  attention span and mental acuity, some have found no 
large differences in these skills between marijuana  users and non-users.

One recent analysis of 15 studies found only minor  effects on memory 
among long-time pot users, and no  clear effect on attention, 
language, reasoning and a  number of other cognitive functions.

One problem is that it's difficult for studies such as  the current 
one to establish a definite  cause-and-effect relationship between 
marijuana and  intellectual deficits, Dr. Lambros Messinis, the 
study's lead author, told Reuters Health.

Though the researchers accounted for a number of  variables -- like 
education, use of other drugs and the  presence of clinical 
depression -- it's tough to  control for all the factors that could 
make heavy marijuana users different from other people, according  to Messinis.

Still, he and his colleagues say, their findings are in  line with 
certain past studies linking heavy, long-term  pot smoking to 
"subtle" deficits in intellectual  abilities.

The study included 40 marijuana users ages 17 to 49 who  were in a 
drug abuse treatment program; all had used  the drug frequently for 
at least five years, but half  -- those considered long-term users -- 
had smoked for  10 years or more. They were compared with 24 adults 
the same age who had used pot no more than 20 times in  their lives.

Overall, both long- and shorter-term marijuana users  performed more 
poorly on tests of memory, attention and  mental-processing speed. 
The proportion of study  participants deemed "impaired," according to 
the researchers, was highest in the long-term group and  lowest in 
the comparison group.
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