Good afternoon, and thank you for inviting me to present. It's a real privilege.
In terms of background, I'm a researcher in cannabis and mental health and a tenured psychology professor at the University of British Columbia where I study issues related to the use of substances. My focus for the past several years has been on cannabis use, both medical and non-medical, and its effects on mental health. I am currently funded by the Canadian Institutes of Health Research and the Social Sciences and Humanities Research Council of Canada to examine the consequences of cannabis use and legalization on the health and well-being of adults. My past work has included some of the largest surveys of medical cannabis users in Canada and an extensive review of the impact of medical cannabis use on mental health. I also lead an ongoing randomized control trial of cannabis for PTSD, which together with a parallel study in the U.S. will be the first to evaluate this treatment. Dr. Bonn-Miller has talked about the parallel study in the U.S.
I'm also a clinical psychologist. As a clinician I've had the opportunity to work with individuals who struggle with the aftermath of trauma. I've worked in the VA hospital in the U.S. and I currently supervise graduate student trainees in the assessment of PTSD. My testimony today is going to draw primarily on my own research and knowledge of the empirical literature on cannabis and PTSD, but is also going to be informed by my first-hand experience in working with individuals who use cannabis to treat PTSD. I want to focus my comments on the stated aims of the committee.
To start off, with regard to the experience and opinions of veterans who have used cannabis for medical purposes, and their family members, I think the reports that we just heard in the previous testimony really speak volumes and I hear many reports in a similar vein. Also consistent with what Dr. Bonn-Miller was saying, the evidence for the effectiveness of cannabis for PTSD is sometimes characterized as not strong, primarily in referring to the lack of randomized controlled trials, RCTs, testing cannabis for PTSD. I agree that such trials will add to our confidence in how best to use, or not use, cannabis for PTSD, and that's why we're currently undertaking that type of research.
However, despite the lack of RCT evidence I do think there is reason to be hopeful regarding the potential for cannabis medicines to help improve the lives of individuals with PTSD. Human studies that are not RCTs deserve attention and Dr. Bonn-Miller's testimony pointed to some of the key features in those studies showing differences in the naturally occurring cannabis system, the endocannabinoid system, of individuals with PTSD, suggesting that alterations in that system might explain the high rates of cannabis use among PTSD patients and certainly point to an important role of that system in the pathology of PTSD. There's converging research that has confirmed an important role for the endocannabinoid system in an emotional response, learning and memory, all of which point to the potential of cannabinoid medicines that interact with those systems.
In addition to advancing brain science, we can learn a lot from patient behaviours, particularly in areas where other evidence, such as RCTs, is currently lacking. Surveys of medical cannabis users identify high levels of use to treat PTSD, and retrospective studies, although methodologically limited, have found that medical cannabis patients report substantial reductions in PTSD symptoms after the uptake of medical cannabis use. Studies also highlight cannabis use helping with sleep and coping with the anxiety that is part of PTSD. Sleep disturbance often emerges as one of the most debilitating PTSD symptoms, and it's one for which there's evidence it may respond to cannabis therapies. Restorative sleep is, of course, key to health and well-being and when it's disrupted, other aspects of health, mental and physical, rapidly deteriorate.
I have spoken with many individuals who use cannabis for PTSD who report going from sleeping in only brief stretches interrupted by terrible nightmares to having their first restful sleep in years after initiating cannabis therapies. As Dr. Bonn-Miller reported, among the benefits of cannabis in PTSD related to sleep disturbance, synthetic cannabinoids have demonstrated good effects in reducing nightmares and improving sleep amongst PTSD patients. I think our experience in Canada and also in the U.S. over the past few years also speaks to the therapeutic potential of cannabis for PTSD. The dramatic increase in enrolment by veterans in the ACMPR and in the preceding programs has caused concern in some quarters, but it's also what we might expect to see from the introduction of an effective treatment: slow and steady increases at first and then a tipping point caused by positive word of mouth leading to exponential growth in uptake.
Of course, patient self-reported efficacy and treatment uptake are not the gold standard for determining the effectiveness of a medication. However, the devastating consequences of untreated PTSD and the limitations of existing treatments make it essential that all promising avenues are explored. Cannabis must be compared to existing options, not to a hypothetical gold standard. With regard to exceptions from the three grams a day maximum, it is true that the quantities of cannabis being used by some veterans may appear excessive, but perhaps no more so than the combinations of prescription medications that are also used to address PTSD as an alternative. For many, the side effects of cannabis are well tolerated compared to those of the antidepressants, sedatives, antipsychotics and other medications, which have side effects such as weight gain, impotence, memory loss and lethargy, all of which dramatically decrease quality of life. In contrast, even at high doses, cannabis is a relatively gentle medication with low toxicity. Perhaps the greatest concern is the development of cannabis dependence. However, effective use of a medication to treat symptoms of a chronic condition need not be considered disordered, and the cannabis withdrawal symptom is short-lived and relatively mild compared to the problems in withdrawing from a number of other medications that may be used for PTSD.
With regard to current research and knowledge about cannabis use for the treatment of medical conditions common among veterans, such as PTSD and pain, one benefit of cannabis therapies is the potential to treat co-occurring conditions and replace several medications. Specifically, a recent comprehensive review from the National Academies of Sciences, Engineering, and Medicine concluded that cannabis was effective for treating chronic pain in adults, which is particularly important given the high rate of opioid use disorder among individuals with PTSD—opioids often started to treat pain. Indeed, growing evidence indicates that cannabis is increasingly being used as an opioid substitute that may reduce fatal opioid overdoses. Reporting from the Globe and Mail that focused specifically on Canadian veterans supports the conclusion that cannabis is being used instead of, rather than in addition to, other medicines.
I think that's so important for understanding the potential benefits of cannabis, whether it's being used on top of or as a substitute for other medications. Research from our group found that cannabis reduced pain, but also helped patients in some cases to be more active, despite chronic pain. Given the negative effects of the isolation that plagues too many veterans with chronic pain and PTSD, the potential of cannabis to facilitate activity and social integration is important, and I look forward to therapeutic interventions that highlight that in combination with cannabis therapy.
Our review of medical cannabis and mental health found that medical cannabis patients overwhelmingly report using cannabis to reduce anxiety in addition to primary complaints of pain. The potential of cannabis to address both pain and anxiety is particularly important in the context of PTSD, given the potential lethality of combining benzodiazepine sedatives and opioid painkillers, both of which are widely used among veterans with PTSD. Cannabis also has the potential to substitute for alcohol, and cannabis may protect against domestic violence, which is also a heightened risk among people who suffer from PTSD.
With regard to the potential effects of cannabis legalization on veterans, I believe that Canada's public health approach will have a positive effect on the lives of veterans. Our research identified fear of negative judgment as an impediment to open communication with caregivers regarding cannabis use. Veterans of mental health conditions who use cannabis bear the burden of a double stigma that could be a substantial barrier to accessing medical care and engaging in frank conversation with their providers. To the extent that legalization reduces stigma, it will have a positive effect on the health of veterans. Legalization will also have a positive effect by fostering research on the development of best practices for the therapeutic use of cannabis.
I certainly agree with Dr. Bonn-Miller that we need to go beyond simply talking about cannabis to talking about how cannabis can work and how it can be integrated with other approaches.
One concern that I do have with regard to legalization involves the per se limits for driving. Veterans who use cannabis therapeutically are likely to consistently exceed the proposed nanogram limits irrespective of acute intoxication. No one should be impaired on the roads, but veterans who use their medication responsibly should not be forced to abandon driving entirely.
Finally, there are the considerations associated with access to health care practitioners to obtain medical cannabis authorization. In our study of medical cannabis users under the MMAR—that was around 2011-12—we examined the extent to which physician communication represented a barrier to access. We found evidence of substantial concern related to perceived stigmatization associated with discussing medical cannabis with a physician. Over half of respondents reported that they wanted to discuss medical cannabis with their physician, but did not feel comfortable doing so. Similarly, over 60% reported worrying about discrimination from physicians related to cannabis use. In general, many patients reported a fear that discussing cannabis with their physician might negatively impact the relationship.
This study also produced evidence that accessing information related to the use of cannabis as a medicine may have been problematic due to limitations with physician communication. Half of respondents reported being relatively dissatisfied with their communications with physicians related to cannabis.
We did a subsequent study under the MMPR and found that many of the obstacles under the MMAR appeared to have persisted under the MMPR at least until 2015; namely, it continued to be difficult for Canadians to find a physician to support their application, and many were charged a fee. In this study we further concluded that affordability and cost of physician evaluations may be a barrier to access for lower-income individuals.
My personal experience as a research scientist who has interacted extensively with medical cannabis patients highlights the importance of access to specific strains of cannabis. Again, this is not one medicine but perhaps many, and we still have a lot of research to do to figure out the distinctions amongst types of cannabis and constituents of cannabis. However, this experience highlights the barriers to accessing specific strains from a specific licensed producer based on substantial variability and product availability. Access to licensed producers is limited by physician communication, and as such, many patients will have access to only a single licensed producer who may not have the desired strain that may be most effective at a given time.
Thank you.