Medical Cannabis Research

Medical Cannabis Research

Docs Develop Clinical Guides for Medical Cannabis

— Physicians strive to provide guidance as patients increasingly ask about treatment

“As medical cannabis gains more mainstream acceptance, and as physicians increasingly encounter patient questions about its use, doctors are developing more clinical resources to guide those who decide to prescribe it.

At this year’s PAINWeek in September, Alan Bell, MD, of the University of Toronto, and colleagues presented recommendations for using medical cannabis to treat chronic pain. The same month, two physicians published a book aimed at helping colleagues treat patients, and the previous month a pain medicine specialist published a similar book.

Though evidence from gold-standard randomized controlled trials has been severely limited, authors of the publications told MedPage Today that it’s important to start somewhere.

“We are trying to advocate for more physicians to provide better care,” said Kevin Hill, MD, of Beth Israel Deaconess Medical Center in Boston, a co-author of one of the new clinical textbooks. “We wanted to present exactly where things stand now — understanding we have a long way to go in some areas.”

Latest Resources

The “consensus recommendations” presented at PAINWeek were supported by Canopy Growth, described on its website as the “first cannabis company in North America to be publicly traded.”

The group met via video calls to develop the guidelines, setting the bar at 75% agreement to include any recommendations, and touting the use of a modified Delphi process.

Ultimately their recommendations included: stratifying patients into conservative, routine, or rapid treatment protocols based on level of need; following a regimen heavy on cannabidiol (CBD), introducing tetrahydrocannabinol (THC) in small doses only when CBD alone cannot yield desired patient outcomes; and starting with 2.5-mg doses of THC and 5-mg CBD doses and increasing dosages by 1-5 mg.

“Our main focus was to provide directions to clinicians to surmount the huge barrier that may exist because of the knowledge gap” about medical cannabis overall, Bell told MedPage Today. “There’s a huge knowledge gap and no way clinicians can fall back on a specified dosing regimen.”

Hill and Samoon Ahmad, MD, of New York University, authored Medical Marijuana: A Clinical Handbook, published by Wolters Kluwer Health in September. The 500-plus-page book features chapters on the endocannabinoid system, adverse effects, pharmacology, among other topics. It also contains 11 chapters on using cannabis within individual medical specialties.

In August, Springer published a similar book edited by Kenneth Finn, MD, a longtime Colorado pain medicine specialist who has written about medical cannabis for KevinMD and MedPage Today. Finn’s 585-page book includes chapters on cannabinoids and pain, dermatology, and public health. Chapters are co-written by clinicians and professors, as well as advocates including Kevin Sabet and David Evans.

Also this summer, Matthew Mintz, MD, who uses medical cannabis in his primary care practice in the suburbs of Washington, D.C., self-published a book for providers and patients based largely on his clinical experience. Bonni Goldstein, MD, a Los Angeles medical cannabis specialist, authored a similar book aimed at both audiences.

“There’s a strong need for good education,” said Leslie Mendoza Temple, MD, director of NorthShore Medical Group’s Integrative Medicine program in Chicago and a board member of the advocacy group Doctors for Cannabis Regulation. “The more we add to the knowledge base, the better it is for everyone.”

Evidence Challenges

The resources seek to provide guidance in a field that lacks a substantial evidence base, in large part because research has been limited by federal regulations and the Drug Enforcement Administration’s Schedule 1 designation. Few randomized controlled trials have been completed, and the aging studies cited in a 2017 National Academies report still serve as prominent sources.

Hill and Ahmad said they aimed to incorporate all the credible research they could find into their book, including new evidence beyond the NAS report, and at a more detailed level. A website affiliated with the book will continuously update as new evidence emerges.

Medical and scientific groups have called for better research into medical cannabis. In May, the Parkinson’s Foundation issued a consensus statement calling for “well-designed studies that will address the question of whether cannabis-based medicines offer therapeutic benefit in the treatment of motor and non-motor symptoms of [Parkinson’s disease].”

The American Heart Association published a scientific statement on medical cannabis in September, highlighting a “pressing need for refined policy, education of clinicians and the public, and new research.” All practitioners “need greater exposure to and education on the various cannabis products and their health implications during their initial training and continuing education,” the statement said.

Just this week, the American Society of Addiction Medicine published a policy statement calling for medical cannabis to be rescheduled “to promote more clinical research and FDA oversight typical of other medications…. Federal legislation and regulation should encourage scientific and clinical research on cannabis and its compounds, expand sources of research-grade cannabis, and facilitate the development of FDA-approved medications derived from cannabis such as CBD or other cannabis compounds.”

On the other hand, some experts have argued existing evidence is enough to work with. Writing in BMJ Open, David Nutt, DM, of Imperial College London, and colleagues criticized British physicians for using the lack of RCTs as a crutch, saying “it is utterly deceitful for people who need it not to be offered medical cannabis.”

Clinicians should evaluate other published evidence, including observational studies and patient-focused trials, he wrote.

Yet the lack of randomized controlled trials has largely prevented British physicians from prescribing medical cannabis since it was legalized in 2018, the paper noted.

Additional Resources Needed

The field still lacks other key resources, such as consensus medical guidelines from a leading medical association, Hill said.

Physicians should scrutinize current resources, experts said. In the consensus guidelines, for example, the 2.5-mg doses and CBD-only treatments lack much evidence to support their use in chronic pain, and using the Delphi process does not make their recommendations science-based, Mintz said.

Mintz took umbrage with extracting guidelines from a poster presentation “not based on true data.” (The guideline task force plans to include more information when they submit for publication, Bell said.)

“It’s an interesting, good start, but calling these guidelines is an overshoot,” Mintz said. “At least there is a consensus group of clinicians. … A lot of what we are using [now] is based on clinical experience.”

The next step would be for the group to develop guidelines based on data, said Jordan Tishler, MD, president of the Association of Cannabis Specialists.

Mintz credited the other resources’ authors for striving to add to the field’s knowledge, regardless of how complete and controversial they may be.

“All physicians should be aware there is some evidence for cannabis and should be aware because it is a good option for some patients,” he said. “The more we can get clinicians, physicians out there saying, ‘yes this is something we can use and here’s a couple ideas how to use it,’ while waiting on federal regulations, that will help.”

“And hopefully we will see the laws change so we can get the data we need.”

Journal of American Geriatrics Society

Clinical InvestigationFirst published: 07 October 2020

Cannabis: An Emerging Treatment for Common Symptoms in Older Adults



Use of cannabis is increasing in a variety of populations in the United States; however, few investigations about how and for what reasons cannabis is used in older populations exist.


Anonymous survey.


Geriatrics clinic.


A total of 568 adults 65 years and older.


Not applicable.


Survey assessing characteristics of cannabis use.


Approximately 15% (N = 83) of survey responders reported using cannabis within the past 3 years. Half (53%) reported using cannabis regularly on a daily or weekly basis, and reported using cannabidiol‐only products (46%). The majority (78%) used cannabis for medical purposes only, with the most common targeted conditions/symptoms being pain/arthritis (73%), sleep disturbance (29%), anxiety (24%), and depression (17%). Just over three‐quarters reported cannabis “somewhat” or “extremely” helpful in managing one of these conditions, with few adverse effects. Just over half obtained cannabis via a dispensary, and lotions (35%), tinctures (35%), and smoking (30%) were the most common administration forms. Most indicated family members (94%) knew about their cannabis use, about half reported their friends knew, and 41% reported their healthcare provider knowing. Sixty‐one percent used cannabis for the first time as older adults (aged ≥61 years), and these users overall engaged in less risky use patterns (e.g., more likely to use for medical purposes, less likely to consume via smoking).


Most older adults in the sample initiated cannabis use after the age of 60 years and used it primarily for medical purposes to treat pain, sleep disturbance, anxiety, and/or depression. Cannabis use by older adults is likely to increase due to medical need, favorable legalization, and attitudes.

Original Paper

Medical cannabis and cognitive performance in middle to old adults treated for chronic pain

First published: 22 September 2020

Sharon R. Sznitman PhD, Senior Lecturer, Simon Vulfsons MD, Director, David Meiri PhD, Lecturer, Galit Weinstein PhD, Senior Lecturer.


Introduction and Aims

Cannabis exposure is becoming more common in older age but little is known about how it is associated with brain health in this population. This study assesses the relationship between long‐term medical cannabis (MC) use and cognitive function in a sample of middle‐aged and old chronic pain patients.

Design and Methods

A cross‐sectional study was conducted among chronic pain patients aged 50+ years who had MC licenses (n = 63) and a comparison group who did not have MC licenses (n = 62). CogState computerised brief battery was used to assess cognitive performance of psychomotor reaction, attention, working memory and new learning. Regression models and Bayesian t‐tests examined differences in cognitive performance in the two groups. Furthermore, the associations between MC use patterns (dosage, cannabinoid concentrations, length and frequency of use and hours since last use) with cognition were assessed among MC licensed patients.


Mean age was 63 ± 6 and 60 ± 5 years in the non‐exposed and MC patients, respectively. Groups did not significantly differ in terms of cognitive performance measures. Furthermore, none of the MC use patterns were associated with cognitive performance.

Discussion and Conclusions

These results suggest that use of whole plant MC does not have a widespread impact on cognition in older chronic pain patients. Considering the increasing use of MC in older populations, this study could be a first step towards a better risk–benefit assessment of MC treatment in this population. Future studies are urgently needed to further clarify the implications of late‐life cannabis use for brain health.