The results of this study indicate many similarities between MC use by male and female Veterans and non-Veterans. Daily amounts of ingested THC, CBD, and the herbal product were similar for Veterans and non-Veterans. Both groups used MC to treat a variety of ailments and reported that MC provided substantial relief for both physical and mental health problems.

The main difference in MC choice was that edibles were more commonly used by Veterans. Reasons for greater use of edibles could be due to the longer duration of action of the ingested product compared with vaporized forms. Stigma associated with inhalation, with the tendency to associate inhaled cannabis with recreational use may also have played a role in the preferential use of orally administered products. Oral administration can also be more discrete as there is avoidance of the smell associated with the inhaled product.

Alternately, cost issues may have influenced the selection of preferred method of administration as MC products are fully reimbursed for Veterans compared with the out-of-pocket expenses for other Canadians. It is possible that the non-Veterans using MC may have accessed the product at times via the less expensive illegal market that focuses mostly on the dried product that is most conveniently inhaled.

Differences between Veterans and non-Veterans regarding MC usage may also arise due to the fact that Veterans have unique health care needs resulting from their military service, including physical injuries, post-traumatic stress disorder (PTSD), traumatic brain injuries, or other service-related conditions.^1,2

These specific conditions could potentially influence the reasons for seeking MC treatment and the effectiveness of its use compared with non-Veterans. In addition, there might be variations in the availability and quality of research, as well as clinical guidelines, for MC usage among Veterans compared with the general population. The unique circumstances and needs of Veterans could influence the focus and direction of research efforts, leading to potentially different recommendations and guidelines specific to this population. It is important to note that the extent of these differences may vary and are subject to further investigation and research.

Consistent with previous studies, these results indicate that MC is commonly used for a variety of physical and mental health complaints such as chronic pain, insomnia, anxiety, depression, PTSD, and arthritis.^14,15 This prevalent use of and satisfaction with MC, often by self-administration, is in contrast to the limited evidence for substantial beneficial effects in the published literature.^4,16,17

Despite the lack of strong scientific evidence demonstrating the effectiveness of MC compared with placebo, there was a strong consistent belief among participants that MC was effective for treating a wide range of physical and mental health conditions. Perceived effectiveness scores were particularly high for mental health problems, with average scores of 8 or greater.

These results are consistent with previous observational studies.^18–22 Whether this represents a placebo effect, regression to the mean, or true efficacy will require more scientific study. These data do provide guidance in targeting these studies to the management of chronic pain conditions and several mental health problems.

On average, MC was used by most respondents several times a day, which was in line with other studies suggesting that the MC provided symptom relief rather than modifying the disease pathophysiology.^{10,18,21,23,24}

A concerning observation of this study is that 60% of the respondents did not identify the strength or content (THC or CBD) of the cannabis product used. This lack of knowledge of product content by many users has been noted in previous studies.^25–27 Although MC is reported to be used as a medicinal product, the poor attention to amount or content of the product may be bolstered by a perception of safety of cannabis as a recreational and natural product.

Alternately, lack of adequate knowledge by both patients and MC prescribers may also be a factor in poor knowledge of content. Further, we have observed limited concerns about safety and side effects of MC, especially from Veterans.

Consistent with other studies, one of the attractions of MC may be that it is used to treat multiple physical and mental health complaints.^{18,20–22,28} These multiple conditions are more prevalent among Canadian Veterans compared with the non-Veteran populations.

This may help with mitigating polypharmacy burden as well as dealing with adherence to complicated pharmaceutical routines and their side effects. However, the complexity of effects of the large numbers of cannabinoid and non-cannabinoid molecules in the plant Cannabis sativa requires both study and understanding before any evidence-based recommendation can be made in this regard.

Sex-based analyses are an important strength of this study. Although sex-based analyses are generally recognized as important tools for detecting disparities and providing insights for research and policy, this strategy has not always been used in research of Veteran populations. We did not observe any significant differences between males and females regarding their MC use patterns. Although males tend to use MC in greater doses, these differences were not statistically significant (p = 0.09).

Considering that females make up roughly 14% of the ∼600,000 Veterans now residing in Canada,²⁹ female Veterans are grossly underrepresented in the literature with many studies reporting on male samples of Veterans (around 70% males).³⁰ There is, thus, an urgent need to address the health-related needs of female Veterans in all future studies.

There are limitations to the current study that must be addressed. First, this was a convenience sample of respondents and the representativeness of these results to the population of users of MC remains to be confirmed. The response rate for this survey remains unknown as recruitment through links on social media or notices sent out by Veterans Affairs Canada does not provide an accurate denominator on how many MC users might have noticed the survey.

Second, the sample size was modest, which may reduce the accuracy of the estimates provided. Third, it is possible that this sample of MC users was biased toward those who found it effective, whereas those who did not benefit did not reply to the survey.

There remain many uncertainties around MC use, particularly among Veterans. Further study should address the specific molecular effects of herbal cannabis products, including various concentrations of THC and CBD, the contribution of other molecules such as terpenes and flavonoids to a therapeutic effect (termed the entourage effect), the interaction of cannabinoids with other medications, and the development of tolerance and importantly, adverse effects especially for long-term use. Ideal dosing as well as methods of administration of MC will also require attention.