CANNABIS LINKED TO MEMORY PROBLEMS

LONG-TERM users of cannabis are risking serious problems with their memory
and concentration, a new study reveals.

The mental problems triggered by heavy use of the drug are serious enough
to interfere with jobs, relationships and "daily functioning", with
symptoms becoming worse the longer a person uses the drug.

A team led by Dr Nadia Solowij of the University of New South Wales
examined the effects of marijuana on 102 regular users - half of whom were
long-term users - and 32 people who did not smoke the drug.

The volunteers, who were recruited from a group seeking treatment for
cannabis dependence, abstained from the drug for an average of 17 hours
before the tests began.

"Long-term users with an average 24 years of regular cannabis use performed
significantly less well on tests of memory and attention than non-user
controls and shorter term users with an average of 10 years use," the
researchers say.

Those who had used cannabis the longest found it harder to recall words
during verbal tests and showed "impaired learning, retention and retrieval".

All cannabis users found it difficult to judge time, the team reports in
the Journal of the American Medical Association.

"For habitual users, the kinds of impairments observed in this study have
the potential to impact academic achievements, occupational proficiency,
interpersonal relationships and daily functioning," the researchers say.

However, further studies are needed to show whether the users recover once
they have given up the drug, they say. Previous studies have found no
evidence linking long-term cannabis use to memory and attention problems.