Health
Headlines
Get
the latest news in prevention and health matters. This
feature includes daily postings and recent archives to
keep you up to date on health reports and wires around
the world.
Weekly
Wellness
Get
informed with weekly wellness facts in a diversity of
health topics from prevention to fitness and nutrition.
Tips
Great
tips on what you need to know about keeping healthy and
active all year round.
Marijuana
Tied To Memory Problems
People who regularly smoke marijuana may
find their memories growing hazy over time, a recent study
published 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 stated.
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.
Long-time pot users showed the greatest problems on tests
where they were asked to learn and remember a series of
words. They were "significantly" below the published norms
for these tests, according to Messinis and his colleagues.
It's not yet clear whether the intellectual deficits
linked to marijuana are lasting, Messinis said, but research
"generally supports" the notion that these problems are
reversible after longer periods of abstinence. People
in his study were required to have been abstinent only
for the 24 hours before taking the tests.
Another unknown, according to Messinis, is whether marijuana
use at a young age may affect the brain differently than
use during adulthood. Knowledge in this area, he said,
is still "poor."
