Pubdate: Wed, 25 Jul 2018
Source: Philadelphia Daily News (PA)
Copyright: 2018 Philadelphia Newspapers Inc.
Author: Ian Haydon, Staff Writer


Despite limited evidence, Americans have an increasingly positive view
of the health benefits of marijuana. Nearly two-thirds believe pot can
reduce pain, while close to half say it improves symptoms of anxiety,
depression, epilepsy, and multiple sclerosis, according to a new
online survey of 9,003 adults.

Pennsylvania and New Jersey are among the 30 states, along with the
District of Columbia, Guam, and Puerto Rico, that have legalized
medical marijuana. But scientists say hard data on the health effects
of pot -- both positive and negative -- are largely missing. Because
marijuana is considered an illicit drug by the federal government,
research has been scant, though there are efforts underway in
Pennsylvania and nationally to remedy that.

"I am not surprised at all [by the survey]. At the same time, I'm a
little bit disturbed," said Antoine Douaihy, senior academic director
of addiction medicine services at the University of Pittsburgh Medical
Center. He was not involved in the study.

Douaihy, who helped legislators craft Pennsylvania's medical marijuana
bill, believes "organizations are not educating the public well" when
it comes to what is known about the benefits and risks of smoking,
vaping, and eating marijuana.

"We don't have enough studies that demonstrate the benefits of medical
cannabis," he said. "And the perceptions about the risks related to
cannabis are going down, particularly among adolescents."

In the survey, a majority of Americans -- 65.7 percent -- said that
marijuana can help with pain management. "There is some evidence which
is moving in that direction, but we need more studies," said Douaihy.
Among the 14.1 percent of respondents who reported using marijuana in
the past year, 87.6 percent identified pain management as a benefit.

Other purported benefits included the treatment of diseases such as
epilepsy and multiple sclerosis; relief from stress, anxiety, or
depression; and improved sleep and appetite. Close to a quarter of all
respondents -- 23.3 percent -- also believe using marijuana can make
it easier to get off other medications.

"Unfortunately we don't know much about that at all," said Douaihy.
Apart from the lack of evidence for disease treatment, few studies
have examined the interactions between cannabis and other prescription
drugs. Patients with chronic health problems often take many
medications. Adding marijuana to that list worries Douaihy, whose
research has largely focused on treating patients with complex
conditions such as addiction coupled with psychiatric disorders.

The survey, published Tuesday in the Annals of Internal Medicine, was
conducted by researchers at the University of California campuses at
San Francisco and Davis, the Northern California Institute for
Research and Education (a nonprofit veterans health research
institute); and Columbia University.

In addition to unsupported beliefs about marijuana's benefits, the
survey also found that more than one in five marijuana users believe
pot has no risks at all.

A worker looks at a marijuana plant at the Desert Grown Farms
cultivation facility in Las Vegas.

Although the risk of developing dependence on marijuana is lower than
with opioids, for instance, "we have clear evidence that [marijuana]
is addictive," said Douaihy, though half of all respondents denied the
link. Among marijuana users, only 20.8 percent recognized the
potential for addiction. "One out of six adolescents who smoke
cannabis gets addicted to it, and one out of 10 adults can get
addicted and have serious consequences," such as withdrawal, Douaihy

Among all respondents, 18 percent said that exposing adults to
secondhand marijuana smoke is somewhat or completely safe. For
marijuana users under 35, roughly 26 percent agreed. That's despite
the fact that inhaling any form of particulate matter damages
cardiovascular health, the authors noted.

Why is public perception at odds with medical research? The survey
authors cite aggressive cannabis marketing, "slanted" media coverage,
and the ongoing trend towards legalization, including for recreational

"It's concerning," said Salomeh Keyhani, lead study author and
professor of medicine at University of California, San Francisco.
"Commercialization has been accompanied by marketing. The internet is
inundated with articles that include inaccurate information that
describe marijuana as not only safe but potentially beneficial for a
wide variety of conditions," she said by email.

Keyhani said there is evidence that purified cannabinoids have some
effect in the treatment of neuropathic pain, as well as nausea and
vomiting associated with chemotherapy. Cannabinoids may also improve
pain and spasticity associated with multiple sclerosis, she noted.

But she cautioned that "the idea that smoking marijuana prevents
health problems has no evidence to support it. Smoking any substance
is hazardous to health as inhalation of particulate matter is harmful."

Douaihy said the medical community "wants to be open-minded. But at
the same time, I'm not going to undermine the risks related to the use
of cannabis."

Keyhani, who received funding for the survey from the National
Institutes of Health and the Northern California Institute for
Research and Education, believes a "coherent federal policy" is needed
for researchers to make progress, as well as more investment in
research and public health education.
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