CONTACT Riggs: 'What was CNN smokin'?' - Dr. Christian Thurstone

Last night, I watched Dr. Sanjay Gupta’s documentary, “Weed,” which aired on CNN and included a snippet of my two-hour interview with the production team. As I previously wrote, I wanted to reserve judgment until seeing it for myself.

Unfortunately, this documentary is one-sided and fails to report clearly on the subject of marijuana as medicine — and the drug’s harms to health.

Dr. Paula Riggs, a professor of psychiatry at the University of Colorado, is a true expert — not a self-proclaimed expert — in the research and treatment of marijuana addiction. She has extensive experience in clinical practice and research and also peer-reviewed publications in the field — unlike some of the the sources Dr. Gupta and the CNN production team chose to feature at great length. She, too, watched the documentary — and wasted no time in sending this letter to Dr. Gupta.

I concur.

Update: The American Society of Addiction Medicine, the United States’ largest professional medical society dedicated to the prevention and treatment of addiction, issued a statement also expressing concern about this documentary. You can read that here. The quick-hit summary of that statement:

ASAM encourages an open and balanced dialogue about the possible benefits and risks of marijuana. The drug may prove to have some clinical application. However, until high-quality, scientific research supports that, and this drug is subject to the same standards applicable to other prescription medications, marijuana cannot be called “medical.”

Dr. Gupta —

I have always held you and CNN in the highest regard, which is why I’m moved to express my concerns (outlined below) regarding some of the material and messaging in the CNN documentary, “Weed,” aired last night. I’m sure you and CNN will give careful consideration to these concerns and other feedback from viewers, clinicians and scientists in addressing any misperceptions related to the information/messaging in the CNN documentary that may have an unintended, negative public health impact.

1. The documentary conveyed that habitual marijuana smokers were less impaired drivers compared to occasional smokers — based on CNN’s anecdotal demonstration that included two individuals. This is in contrast to a substantial body of research (Crean et al 2011 and others) showing that chronic, daily use, or near daily use, in adults is associated with impaired executive functioning and persistent neurocognitive deficits (abstract reasoning, verbal fluency, decision making, working memory) that last at least one month even with sustained abstinence. Moreover, the messaging in the documentary could certainly be construed as encouraging regular marijuana (daily or near daily use) versus occasional marijuana use, which could further increase the number of individuals meeting criteria for cannabis use disorder and/or addiction. More concerning is the suggestion that it’s safe to drive under the influence of marijuana while acutely intoxicated IF you’re a habitual or experienced marijuana smoker. This is not consistent with the significant increase in marijuana-related motor vehicle accidents and fatalities documented in Colorado and other medical marijuana states since 2009.

2. The documentary clearly promoted the use of smoked “medical” marijuana and did not mention alternatives, such as synthetic THC. (example: Marinol)

3. The documentary did indicate that marijuana is “addictive,” stating that 9 percent (or 1 in 11) of individuals who smoke marijuana progress to addiction or dependence. However, CNN did not distinguish between adults and adolescents — who have been shown to have greater vulnerability to cannabis addiction. 1 in 6 adolescents who experiment with this drug progress to dependence and/or addiction (versus 1 in 10-11 adults).

4. The documentary created confusion about the potential benefits of Cannabidiol, also called CBD, versus the high THC content of most medical and recreational marijuana products. I was most concerned by the suggestion that cannabis may be neuroprotective (e.g, “build her brain”). This is in contrast to a large body of research showing marijuana to impair memory –especially working memory — and interfere with the ability to convert short-term to long-term memory. Chronic use of marijuana has been shown to destroy neurons, dendritic connections, white matter tracks in the hippocampus and other brain areas with high concentrations of cannabinoid receptors.

5. Although there are certainly individuals with medical conditions whose use of marijuana supports more research, the CNN documentary was scientifically imbalanced and irresponsible in suggesting positive health and psychological benefits for which there is little to no evidence. Anecdotal cases presented in “Weed” ranged from:

– enhanced creativity (n=1; Does CNN REALLY want to suggest this as a legitimate indication for “medical marijuana?”);

– miracle cure for intractable seizures in one child (n=1);

– PTSD/trauma (n=1). To suggest that medical marijuana is an effective treatment for PTSD/trauma/and/or “psychic pain” (as suggested in your reporting about the Holocaust survivor) undermines and disregards a very large body of research on effective treatments for PTSD and/or trauma with proven efficacy/effectiveness.

6. The many positive claims of health benefits associated with medical marijuana were not balanced by the scientifically known health risks associated with marijuana use -— regardless of whether it’s called “medical” or “recreational,” including:

– prenatal marijuana exposure, which has been shown to cause long-term deficits in memory, learning , attention, early-onset depression (by age 10), and onset of conduct problems/delinquent behavior and cannabis use by age 14. The strongest associations were with first trimester exposure, when women are less likely to be aware that they are pregnant. These findings were based on a 14-year longitudinal study comparing women who smoked less than 1 joint per day versus those who smoked more than 1 joint per day during pregnancy (Goldschmidt et al 2012 ). Research shows that 1/3 of THC crosses the placenta — and it’s important to note that the marijuana smoked by the pregnant women participants in this study more than 15 years ago was almost certainly far less potent than most medical marijuana products sold today.

(Dr. Riggs added this side note when sharing her letter with colleagues: “I’ve been asked to develop language for the product ‘warning label’ for marijuana products sold in Colorado, which will include: “Marijuana should not be consumed by women who are, or who may be, pregnant because of risks to fetal development.” Two members of Gov. John Hicklenlooper’s regulatory task force stated that some OB/GYN practices in Denver/Colorado are actually recommending ‘medical marijuana’ to patients experiencing nausea related to ‘morning sickness’ during the first trimester of pregnancy.”)

– significant increase in hospitalizations related to inadvertent marijuana exposure (ingestion of medical marijuana edibles) in children (infants-age 12) based on recent study published in the Journal of the American Medical Association. (Wang et al 2013)

– significant increases in the number of cases of cannabis hyper-emesis syndrome, a condition in which people cannot stop vomiting, (presenting to emergency department, complicating the course of withdrawal/detox) in Colorado and other medical marijuana states.

There is substantial evidence that marijuana is neurotoxic to adolescent brain development. According to the most recent Monitoring the Future Survey (2012) conducted at the University of Michigan, 45 percent of high school seniors nationwide (61 percent in Colorado) report lifetime use of marijuana. In Colorado and other medical marijuana states, marijuana use among high school students is considerably higher than national norms largely due to increased access to high-potency marijuana. Currently, one in 20 high school students nationwide, and one in 15 high school students in Colorado, are using marijuana at levels associated with an average eight-point reduction in their adult IQ and persistent neurocognitive deficits (Meier et al 2012; Pope et al 1998; Brook et al, 2008).

I consider this a public health crisis comparable to the impact of environmental lead poisoning associated with an average 7.4 point reduction in IQ with exposures of 10 micrograms per deciliter (Canfield et al 2003, NEJM).

Respectfully submitted,

Paula Riggs, M.D.
Professor of Psychiatry
Director of the Division of Substance Dependence
University of Colorado School of Medicine

About Chris Thurstone

Dr. Christian Thurstone is one of only a few dozen physicians in the United States who are board-certified in general, child and adolescent and addictions psychiatry. He is Director of Behavioral Health Services at Denver Health and a professor of psychiatry at the University of Colorado, where he conducts research on youth substance use and addiction and serves as director of medical training for the university’s addiction psychiatry fellowship program. You can read more about him here.

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