POPULAR OPINION IS NOT SCIENCE

On July 11, the Post-Gazette reported on Pennsylvania's efforts to
legalize medical marijuana ("The Push for Pot: State Bill Would Legalize
Marijuana as Therapeutic Option"). For both alleged medical reasons and
admitted financial ones -- and rationalizing that the popular vote is
there -- legislators ask, why not?

Everybody knows it, but maybe it's a good time to say it again:
Popular opinion is not science. In fact, the two have little in common.

There is scientific evidence that marijuana is addictive. Recent
developments in neuroimaging techniques show distinct similarities
between the way the brain changes in response to cannabinoids and the
way it changes to exposure to other addictive drugs: The brain
develops a tolerance, can experience cravings and can suffer
withdrawal -- all marks of addiction. Some marijuana users express a
desire to cut back or quit, but have difficulty doing so -- a hallmark
in assessing dependence. Like all drugs, not everyone who uses
marijuana becomes dependent on it. But some do.

Regarding medical marijuana, it has been argued as an option in
treating certain conditions, such as nerve pain or
chemotherapy-related nausea. Using addictive substances to treat
medical issues, while not new, does require thorough patient education
and consent and careful -- very careful -- medical monitoring, which
is not the case in California where medical marijuana has been
legalized. We also need to do more research on the effects of medical
marijuana use on people's lives in general, e.g., relationships, work,
productivity and long-term health and quality of life. We simply don't
understand this very well yet. Other nonaddictive proven remedies also
exist.

Too often, our understanding of addiction is informed by emotion,
prejudice, stigma or financial need, rather than scientific rigor.
Privileging public opinion over science on the issue of legalization
is inappropriate, particularly when the public can be so easily
motivated by a desire to reduce tax liability or for a fleeting but
potentially life-altering good time.

Michael T. Flaherty, Ph.D.

Executive Director

Institute for Research, Education and Training in the Addictions Downtown