Riggs: ‘What was CNN smokin’?’

Aug 12, 13 Riggs: ‘What was CNN smokin’?’

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


  1. It’s ironic that the utter paucity of critical thinking exhibited by those who favor the legalization of marijuana is matched only by that which was exhibited by those who favored its criminalization. Anecdotal evidence, however much it pulls at one’s heartstrings, is not science, and it’s just plain stupid to legalize a psychoactive drug before it’s been subjected to rigorous, unbiased research and its potential dangers are clearly understood and publicized. It’s also ironic that a highly regarded physician such as Dr. Gupta, whose training and practice has been solidly grounded in the scientific method, should come to such hasty conclusions about marijuana’s medical benefits. Remember that cocaine and heroin were once freely prescribed by doctors and even available in over-the-counter medicines. Intelligent, responsible people learn from the mistakes of the past. If marijuana is a miracle drug, it has to prove itself in the same way that anti-HIV drugs and the polio vaccine had to.

  2. Ralph Nolen /

    Sure.. I bet you have LOTS of stocks in the pharmaceutical industry…

    • Christine Tatum Thurstone /

      Thanks for writing, Ralph. Drs. Riggs and Thurstone have no stock and/or other direct financial interests in any pharmaceutical company. Because of their research, they routinely disclose their financial interests.

  3. Thank you Dr. Riggs for your letter and your continuing efforts to publicize the known health risks associated with marijuana use. I also agree with the comments posted above. I would love for Dr. Gupta, to do a follow-up story. But, instead of the individual stories, he should focus on the bigger picture. What does the population of medical marijuana patients look like? The statistics on patients on the Colorado Medical Marijuana Registry should give Dr. Gupta pause. Numbers provided yesterday by the Colorado Department of Public Health and Environment in response to a Colorado Open Records Request show that thousands of young people under 21 are “medicating” with marijuana. As of August 13, 2013, there are 4,528 people ages 18-20 on the registry. This is 4.3% of the total registrants. These people are predominantly male, 78.1% (3,536) and in pain. A whopping 93.6% (4,238) of registrants in this age category list severe pain as a reported medical condition; 72.2% (3,269) list severe pain as their ONLY medical condition.

    • Deborah /

      It is a sad person who is afraid of open discourse, and the author of this piece is exactly that. The reason you see so many supportive comments is because they do not allow anyone with a differing opinion to comment.

      • Christine Tatum Thurstone /

        We welcome hearing from readers who elevate discussion threads and advance arguments coherently and logically. So many commenters fail to meet our commenting rules, which are posted here.

  4. Dave C. /

    although I agree with some of the comments stated above, and the possibility of addictiveness….it is clear the Marijuana does have medical benefits. It is time to decriminalize the herb, and start spending money on studying it. Clearly chemotherapy and its sister type treatments are not the only nor probably the best answer. Harming someones body with powerful radiation cannot be the only cure. I think had/if we had spent all the money on Marijuana and herbal/nutritional therapies we may have just found a cure. Also, why should we synthesize THC? how ludicrous…The natural type is effective enough. The only reason to synthesize it, is so the phamacuetical companies can call it a drug and have it approved by the FDA. The FDA will not approve anything natural as a drug, and will not consider it a “drug”. The hyprocracy and profits keep it illegal…plain and simple. Until it is legalized it cannot be correctly studied.

    • Christine Tatum Thurstone /

      Thanks for writing, Dave. We appreciate your input and agree wholeheartedly with you that the ingredients of cannabis should be researched to determine their efficacy for a wide range of health problems. Dr. Thurstone has written this repeatedly — most recently here. Smart Approaches to Marijuana, also known as Project SAM, a national organization Dr. Riggs and Thurstone help direct, also champions research of cannabis. We hope you’ll read more here.

      Synthesis of THC isn’t necessarily ludicrous — especially when it can be combined with other substances to make effective medications. It’s also very important to note that effective drugs extracted from cannabis and developed in responsible and rigorously vetted research settings already exist. One example, Sativex (1:1 ratio of THC and CBD) is approved for use in parts of Europe and expected to win U.S. Food and Drug Administration approval in about a year. It’s not a synthesis of THC.

      So, whether we’re dealing with synthetics or the real deal doesn’t matter to us. It’s the process by which any substance earns the title “medicine” in the United States that counts. We agree with the American Society of Addiction Medicine: “Marijuana may prove to have some clinical applications. But until and when high quality scientific research supports that, and the drug is subject to the same standards that are applicable to other prescription medications, marijuana cannot be called ‘medical.’”

  5. Christy Brown /

    Thank you, Dr. Riggs. It is ironic that before the show aired Gupta said he would not “permit” his children to use marijuana until they were adults because of effects on the brain, but that was downplayed by the media. In California where I live it is common for 18 year olds (who often have already been smoking marijuana for years in secret without parents’ “permission”) to get a recommendation from a pot doctor, even if they are addicted to marijuana or have mental health issues, or their use is actually recreational. Medical marijuana is being diverted to high school students by some of these younger users. I did not give “permission” to my child to smoke marijuana, and I explained the risks of marijuana on lungs and brains numerous times, but he smoked it anyway in secret, became addicted, and experienced severe consequences. Dr. Gupta thinks marijuana has a “low potential for abuse” because fewer people become addicted and one cannot overdose, but for young kids to use marijuana and become fixated on it keeps them from developing their potential and it can definitely lead to other drugs. A large percentage of high school and college students using marijuana, many on a daily basis in school and while driving, combined with high alcohol use, is to me a high potential for abuse. When it is your child who is affected, Dr. Gupta, addiction is a nightmare because none of the educational, social, or psychological milestones of adulthood are achieved.

  6. Outstanding letter Dr. Riggs. I think CNN should do a follow on. Perhaps they can start in California where high potency pot, which is bio-engineering to eliminate CBD in favor of THC, is in vogue. They could show our national forests being decimated by marijuana farms, and pot doctors who issue recommendations to 18 year old kids within seconds if they have $20. For $335 you can get a recommendation for Dr. Skype (as we call him) to grow 99 plants, the equivalent of somewhere between 118,000 and 594,000 joints. The two age groups with the highest consumption of marijuana are 18-25 followed by 12-17, both below the threshold of a mature brain. The 20-30% of young people damaging their brains will continue to be a burden on the 70-80% of those who didn’t, as they fill our prisons, mental health facilities, cause more traffic deaths and burden the welfare system.

  7. I really appreciate this “side” of the story. I watched this report and found that it would be incredibly easy to listen to Dr. Gupta (because, he is, after all, Dr. Gupta), not parse words and come away with the belief that we have over-reacted to the use of marijuana. As a parent of teenagers, my concern is that kids hear some reports and do not have the knowledge or understanding beyond what they hear. Watching “Weed” and reading Dr. Gupta’s columns recently posted will likely lead many young people to believe that smoking marijuana is providing a “medicinal value” to their life. In fact, they are destroying their developing brain. The fact that the issue can be rather confusing anyway, it just got more confusing and this is all to the detriment of our youth. Thank you.

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