Pubdate: Fri, 13 Jan 2017
Source: Baltimore Sun (MD)
Copyright: 2017 The Baltimore Sun Company
Author: Melissa Healy


Marijuana's health effects

A new report says the precise health effects of marijuana on its users
remain something of a mystery. (Jan. 13, 2017)

More than 22 million Americans use some form of marijuana each month, and
it's now approved for medicinal or recreational use in 28 states plus the
District of Columbia. Nationwide, legal sales of the drug reached an
estimated $7.1 billion last year.

Yet for all its ubiquity, a comprehensive new report says the precise
health effects of marijuana on those who use it remain something of a
mystery -- and the federal government continues to erect major barriers to
research that would provide much-needed answers.

If historical patterns are any guide, ballot initiatives that legalized
recreational marijuana in California, Maine, Massachusetts and Nevada last
year will lead to an increase in cannabis use and drive down public
perceptions of the drug's risks. The result could be a natural experiment
on a grand scale, according to the report released Thursday by the
National Academies of Sciences, Engineering and Medicine.

"This lack of evidence-based information on the health effects of cannabis
and cannabinoids poses a public health risk," a panel of 16 experts
concluded in the first comprehensive look at marijuana research since

The report, nine months in the making, assessed more than 10,000 studies
that examined marijuana's relationship with cancer, psychiatry, accidents
and a host of other health issues. The authors included physicians, public
health experts, neurobiologists and addiction specialists.

Happy New Year and pass the pot. But now that weed is legal for adults in
California, we need somehow to keep more teens from toking.

California's Department of Public Health was one of 15 sponsors of the
report. Department spokesman Matt Conens said in a statement that it hoped
"to gather credible information" to protect patients and the public and
guide the state's cannabis-related public health response, and is
reviewing its recommendations.

Some things were clear. The report authors concluded with confidence that
marijuana and products that mimic its psychoactive effects can provide
effective treatment of chronic pain and help some patients with sleep.
Cannabis and cannabinoids, they wrote, effectively ease
chemotherapy-induced nausea in cancer patients and spasticity in those
with multiple sclerosis.

There is "substantial evidence" that women who use marijuana during
pregnancy are more likely to give birth to smaller babies who face a range
of early disadvantages. The report also detailed strong evidence that
long-term pot-smoking is linked to worsened respiratory symptoms and more
frequent episodes of chronic bronchitis. And it found solid research
findings of an overlap between frequent users of marijuana and those who
develop schizophrenia or other psychotic disorders, though it's not clear
whether one causes the other.

At the same time, the authors warned that many of the conditions for which
patients have turned to medical marijuana have little or no research that
demonstrates its effectiveness. Those include the use of cannabis or
cannabinoids for treatment of epilepsy, Parkinson's disease symptoms and
support of abstinence from addictive substances.

Also thin, according to the new report: research that clarifies the
relationship between drugged driving and accidents. The statistical link
between marijuana use and an increased risk of motor vehicle crashes is
"substantial." But that might be because those most likely to drive under
the marijuana's influence -- young men and people who also use alcohol and
other drugs -- are already more likely to get in accidents.

While it's possible to measure the concentration of marijuana's active
agent, THC, in the blood of drivers, researchers aren't really sure at
what concentration impairment -- or, for that matter, beneficial effects
- -- kicks in, the experts wrote.

That's a crucial research gap for state legislators looking to draft laws
against driving under the influence. Indeed, the panel members wrote, it's
not even clear that measures focusing on marijuana use alone would save

Overall, the report suggests that, like many drugs, marijuana can be
powerful medicine at some doses and to some people, and potentially
dangerous in other strengths and to other people. The body of available
research doesn't provide a clear guide to who will reap those benefits or
incur those harms, and how dosage or mode of administration could spell
the difference.

"What do we really know for sure? Mainly it's anecdotes or very poor
evidence," said Dr. Marie McCormick, a maternal and child health expert at
Harvard's School of Public Health who chaired the National Academies

Given the continuing tug-of-war between the states and the federal
government over marijuana policy, it's unlikely that new research will
provide better answers any time soon. Those who wish to investigate
marijuana's effects face high legal and bureaucratic hurdles, the panel

When most federally funded researchers put marijuana's properties to a
rigorous test, they have one legal source to turn to: a University of
Mississippi facility that has cultivated the plant for the National
Institute on Drug Abuse since 1968.

Commercially available marijuana and derivative products have changed
dramatically since then, becoming more potent, more concentrated and
available in forms that can be consumed and vaped as well as smoked. These
changes aren't reflected at the growing facility; in most cases, it offers
the plant's leaves and flowers in a narrow range of concentrations. Only
in July did NIDA ask researchers how its marijuana products might better
serve their research needs, the panel said.

Rules governing marijuana research can also be forbidding, the panel added.

Federally funded marijuana researchers must get an OK from the Drug
Enforcement Agency and in some states, a state board of medical examiners.
The DEA requires researchers to erect elaborate security measures to limit
the number of people who come into contact with marijuana provided for

"This process can be a daunting experience for researchers," the panel wrote.

Meanwhile, testing the health effects of marijuana products that are
actually marketed to consumers is illegal, according to the report. Even
as sales of cannabis concentrate (often called "dabs") doubled in Colorado
between 2015 and 2016, federal law prevented biomedical researchers from
conducting research on its benefits or harms, blocked chemists from
examining its safety, and barred neuroscientists from gauging its effects
on the brains even of lab animals.

While marijuana "edibles" are a booming part of the consumer market,
federal law also bars scientists from testing these products for
contaminants, investigating their effects on patients with certain medical
conditions, or administering them to lab animals.

"The federal government continues to enforce restrictive policies and
regulations on research into the health effects or harms of cannabis
products that are available to consumers in a majority of states," the
report said. Those strictures are "leaving patients, health care
professionals and policy makers without the evidence they need to make
sound decisions regarding the use of cannabis and cannabinoids."

Tarek Tabsh, who operates medical marijuana dispensaries in Los Angeles
and Las Vegas, said he's concerned about the dearth of reliable
information about the products his industry sells. In particular, he said,
it's important to understand how the industry's customers will be affected
by the increasingly concentrated products that are coming on the market.

"I question the value of a lot of current research," said Tabsh, who
hailed the report's call for changes.

"The biggest fear I have has nothing to do with policy or commerce," he
added. "It has everything to do with science."
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