Study shows marijuana increases brain cell growth

By Juanita King, The Muse
(Memorial University of Newfoundland)

ST. JOHN'S, Nfld — Supporters of marijuana may finally have an excuse
to smoke weed every day. A recent study in the Journal of Clinical
Investigation suggests that smoking pot can make the brain grow.

Though most drugs inhibit the growth of new brain cells, injections
of a synthetic cannibinoid have had the opposite effect in mice in a
study performed at the University of Saskatchewan. Research on how
drugs affect the brain has been critical to addiction treatment,
particularly research on the hippocampus.

The hippocampus is an area of the brain essential to memory
formation. It is unusual because it grows new neurons over a person's
lifetime. Researchers believe these new cells help to improve memory
and fight depression and mood disorders.

Many drugs -— heroin, cocaine, and the more common alcohol and
nicotine — inhibit the growth of these new cells. It was thought that
marijuana did the same thing, but this new research suggests
otherwise.

Neuropsychiatrist Xia Zhang and a team of researchers study how
marijuana-like drugs — known collectively as cannabinoids — act on
the brain.

The team tested the effects of HU-210, a potent synthetic cannabinoid
similar to a group of compounds found in marijuana. The synthetic
version is about 100 times as powerful as THC, the high-inducing
compound loved by recreational users.

The researchers found that rats treated with HU-210 on a regular
basis showed neurogenesis — the growth of new brain cells in the
hippocampus. A current hypothesis suggests depression may be
triggered when the hippocampus grows insufficient numbers of new
brain cells. If true, HU-210 could offer a treatment for such mood
disorders by stimulating this growth.

Whether this is true for all cannabinoids remains unclear, as HU-210
is only one of many and the HU-210 in the study is highly purified.

"That does not mean that general use in healthy people is
beneficial," said Memorial psychology professor William McKim. "We
need to learn if this happens in humans, whether this is useful in
healthy people, and whether THC causes it as well."

McKim warns that marijuana disrupts memory and cognition. "These
effects can be long-lasting after heavy use," he said. "This makes it
difficult to succeed academically if you use it excessively."

"Occasional light use probably does not have very serious
consequences. [But] there is some evidence that marijuana smoke might
cause cancer."

Still, the positive aspects of marijuana are becoming more plentiful
as further research is done. McKim says it's not surprising that THC
and compounds like it could have medicinal effects.

"Many have been identified," he said. "It stimulates appetite in
people with AIDS, it is an analgesic, and blocks nausea in cancer
patients undergoing chemotherapy. And it treats the symptoms of
glaucoma."

The research group's next studies will examine the more unpleasant
side of the drug.