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An Open Letter to Dr. Mark Levine
 Re: Urgent Need to Inform Legislature of Your Position on the Cannabis Warning

Mark Levine, M.D.


Vermont Department of Health

Dear Dr. Levine

 Vermont physicians ask for your help to provide a reasonable standard of care to our patients suffering harms of cannabis use. The science is settled on a number of cannabis induced harms. The treatment of these acute and chronic conditions inherently relies on the patient stopping cannabis use.


To this end in November 2021 Vermont Medical Society (VMS) issued their recommendation of a 31-word warning label on cannabis to be sold legally in the state (incidentally just days after the CCB submitted their 141-word warning label). The CCB version fails to warn the public of cannabis induced psychosis, cannabis hyperemesis syndrome, self-harm, or addiction.  The 31-word VMS warning states:


Cannabis/THC may cause: 1. Psychosis* 2. Impaired driving 3. Addiction 4. Suicide attempt* 5. Uncontrollable vomiting 6. Harm to fetus/nursing baby *This can occur in individuals with no previous history of psychosis or mental illness.


The VMS and others wrote to the Cannabis Control Board, to urge them to revise their proposed warning by adopting this one. We received no response. However, in the CCB’s submission to the Legislative Committee on Administrative Rules the Board defended its rejection of the VMS warning solely on the grounds that you and your Department had approved of the 141-word version. See Feb. 3, 2022 Submission to LCAR pdf p.79.

We believe the CCB may not correctly understand your views. You have written to one of us that you have researched this, spoken to psychiatrists from Colorado and you have mentioned also having treated cannabis induced psychosis in your own internal medicine practice “and the issues are well known. Vermont Department of Health and the Vermont Medical Society are all aligned on this and do indeed warn on the risks.”


You were certainly correct. The peer-reviewed literature strongly supports the causal link between cannabis consumption and psychosis, impaired driving, addiction, self-harm/suicide attempts, cannabis hyperemesis and harm to fetuses and nursing infants. Hundreds of articles support the link to psychosis. Still psychosis has been questioned by the CCB in its January 15, 2022 report to the legislature; unfortunately the CCB relied on a study from Minnesota from a time before high THC was generally used. Furthermore, the 2006 report by Wayne Hall, PhD, which the Vermont CCB cites has been overwhelmed since then by contrary studies, and Dr. Hall wrote in 2020 in support of the fact that “cannabis is a component cause of psychosis”, as Dr. Robin Murray has said. See Murray and Hall, “Will Legalization and Commercialization of Cannabis Increase the Incidence and Prevalence of Psychosis?”, JAMA Psychiatry 4/8/20, p.E1. Dr. Robin Murray, one of the most cited researchers in schizophrenia, has said that ‘no serious scientist continues to dispute that cannabis is a component cause of psychosis’.


As a scientist following science driven public health policy, we know that you are aware of the now overwhelming evidence and agree.


In Colorado, cannabis has been commercially available for medical use since 2000 and for non-medical use since 2012. Importantly now the state has overhauled their law because of the increasing cases of psychosis, cannabis hyperemesis and other cannabis related disorders they are seeing. The State now requires the following warning be provided to every purchaser of marijuana concentrate (concentrated THC is defined in their document as greater than 10% THC):

If the Vermont CCB’s conclusion that cannabis has no role in psychosis is true, Colorado with years of experience commercializing and concentrating the drug, would not have felt compelled to warn their public of psychosis and use disorder. Public outcry and analysis of the science by the state’s leading doctors in Colorado led to this change in the law. The difference between the CCB warning and the VMS warning, for some Vermonters, may be the difference between sickness and health. There is important, basic information that needs to be read and understood. The 141-word version will not be read.  Attached to this letter is a side-by-side comparison of the CCB version and the VMS version.

As you know, cannabis hyperemesis syndrome did not substantially exist before cannabis commercialization, and it can be expensive to diagnose and treat. As with cannabis induced psychosis, the treatment of choice is the cessation of cannabis use. Until users see this medically known connection in the warning, they won’t suspect there is a connection and generally continue or increase their cannabis consumption in a futile attempt to mitigate the hyperemesis. See patients speaking here of their excruciating pain and simultaneous lack of awareness.

Vermont has one of, if not the highest, cannabis use rates in the nation, both for teens and adults, and our emergency rooms and primary care doctors are seeing these harms in their patients. Paradoxically, as problem use has increased, the public’s perception of harm in Vermont has decreased. In the current environment, it is nearly impossible to convince a suffering patient (or the family and loved ones) of the need to halt cannabis use to treat the patient’s suffering as our current standard of care, given the medical knowledge of the settled science now available, would require.


Thus, this lack of awareness of the known harms of cannabis use is adversely impacting our ability to provide an adequate standard of care for Vermont patients.


As with tobacco, changing behavior first requires awareness. Health warnings are an effective and low-cost approach to educating the public. Labeling is an effective approach to educating the public at NO added cost to government or consumers.


The Cannabis Control Board has stated that they embrace the long 141-word warning because this is the recommendation of the Vermont Health Department.


Your service over the past two years has been extraordinary.  We know your plate must be very full. We hope that you can take the time, now, to inform the LCAR that the shorter but more medically correct and complete version has your support. 


THEREFORE, we request, to avoid unnecessary suffering by our patients, who are often unaware and may buy product without a warning of these specific potential health impacts, which we now know to be settled medical science, that you inform the Legislative Committee on Administrative Rules that you support our recommendation to the legislature to follow the science and require the Vermont Medical Society’s 31-word warning label instead of or integrated into the current 141-word warning which fails to mention cannabis induced psychosis, cannabis hyperemesis syndrome, self-harm, or addiction. These changes are similar to those in Colorado that we now see required by law to warn patients and the public in general. Currently standard of care requires at a minimum these science based public health warnings.

[New 2022 Colorado] WARNING

Use of Marijuana Concentrate May Lead to:


  1. Psychotic symptoms and/or Psychotic disorder (delusions, hallucinations or difficulty distinguishing reality);

  2. Mental Health Symptoms/Problems;

  3. Cannabis Hyperemesis Syndrome (CHS) (uncontrolled and repetitive vomiting)

  4. Cannabis abuse disorder/dependence (including physical and psychological dependence).

Dr. Catherine Antley

Dr. Kim Blake

Dr. David Butsch

Dr. David Charnock

Dr. Deborah Henley

Dr. John Hughes

Dr. Janet Kirwan

Dr. Debra Lopez 

Dr. J. Marty Linseisen

Dr. Joe Nasca

Dr. Paul Parker

Dr. Paul Reiss

Dr. David Rettew

Dr. John Reuwer

Dr. Robert Tortolani

Dr. Amanda Van Straten

Dr. Anne Vitaletti-Coughlin

Dr. Linda Zamvil


Doctors continue to sign on daily. Please check back regularly.

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