We conducted an extensive retrospective study with the objective of describing the population of patients seeking treatment with medical cannabis at 33 clinics in the US. Our results indicate that patients seeking medical cannabis in the US most commonly report suffering from unspecified chronic pain (57.0%), regardless of age or gender, which is consistent with similar studies that report 61.2 to 82.6% of patients seeking medical cannabis for chronic pain (Boehnke et al. 2019; Sexton et al. 2016; Eurich et al. 2019; Reinarman et al. 2011). Second to unspecified chronic pain, patients were most likely to report anxiety as their primary medical condition, and anxiety was the most commonly reported comorbid condition. This finding is consistent with results from a survey completed by Sexton et al. among self-identifying medical cannabis patients, in which the second and third most common medical conditions that patients reported using medical cannabis for were anxiety (58.1%) and depression (50.3%) (Sexton et al. 2016). Gender was a significant predictor for most primary conditions, which is unsurprising as males and females have different risk factors, experiences and perceptions of illness and do not tend to report or be diagnosed with medical conditions in equal proportions (Seeman 1997; Buvinić et al. 2006; Westergaard et al. 2019).

The average number of conditions and comorbidities is not commonly stated, but has been reported at 1.8 and 3.0 in similar studies, both lower than our findings (Reinarman et al. 2011; Salazar et al. 2019). The average number of conditions reported differed between males and females, with females reporting a higher average number of conditions. This aligns with previous research that has demonstrated that females access health care services more than males and may be more diligent with providing relevant information, which may partially explain why females tend to have higher reported rates of morbidity (Bertakis et al. 2000; Verbrugge and Wingard 1987; Waldron 1983; MacIntyre et al. 1999).

Similar to the survey by Salazar et al., this study also demonstrated the wide variety of conditions for which patients access medical cannabis (Salazar et al. 2019). Conditions representing less than 1.0% of sample accounted for 10.6% of primary conditions reported and included more than 200 unique conditions (Table 8), the majority of which came from states where physicians are able to use their discretion for patients’ qualification (MA, MD, ME, MO). The information on the number and variety of conditions for which patients report seeking medical cannabis treatment is important for medical practitioners for several reasons. Firstly, it highlights the breadth of conditions for which patients are seeking medical cannabis for symptomatic relief. This is important as it identifies patients who may potentially turn to them with questions regarding their suitability for medical cannabis or who may already be seeking medical cannabis without their knowledge, demonstrating the need for practitioners to educate themselves and be prepared to discuss and provide their professional medical opinion. Secondly, these data demonstrate that patients seeking medical cannabis are complex patients who have more than a single ailment. While rigorous clinical trials are still needed to validate the use of medical cannabis for these conditions, real world data are also needed to describe these patients, as complex patients are more likely to be excluded from clinical trials evaluating the effectiveness of a medication (Hanlon et al. 2019). Finally, these data highlight the potential utility of medical cannabis and how it is currently utilized for treatment of multiple conditions with which a patient is suffering.

Medication use and average number of medications increased with age; however, patients reported medication use less than the general US population overall. Findings from the National Health and Nutrition Examination Survey reported that 83.6% of adults aged 60 and over used prescription medication in the previous 30 days, compared to only 56.4% of our sample aged 60 and older. For adults aged 40–59, our sample also reported less medication use; 48.3% compared to 59.5% (Martin et al. 2015). This difference may be a result of patients under-reporting their medications at the clinic, or medication information not being correctly transcribed into the software from practitioners’ notes. Alternatively, it may show a true difference in characteristics between the general US population and those accessing medical cannabis. The latter may suggest that those accessing medical cannabis may be doing so in lieu of using traditional pharmaceutical medications; however, this theory contradicts results of a study from 2018 that reported that medical cannabis users are more likely to use prescription medications (Caputi and Humphreys 2018). Reported medication use was not analyzed in reference to specific primary medical conditions for the purposes of this study, but identified it as an area of interest for future research. It is interesting to note that 26.1% of the sample did not report using medications or alternate therapies at the time of their initial assessment. This may demonstrate a limitation of the data, as there is potential that there is under-reporting at the system level; however, this may also indicate that patients are seeking medical cannabis where other treatments have failed, which would benefit from further investigation.

When comparing our results to a study of 1746 patients attending assessment clinics in California in 2006, who were primarily male (72.9%) and between the ages of 25–54 (69.2%) (Reinarman et al. 2011), it suggests that the medical cannabis patient population has evolved over time to include more females, and a wider range of ages; 40% of the sample who reported gender were female, and 31.5% of the patient population in this study were over the age of 54. The increasing age of medical cannabis users and increase in female users were also reported in a review completed by Fairman et al. (Fairman 2016). The high representation of Caucasians in this sample is consistent with the literature in which Caucasians represent the majority of medical cannabis users reported in other studies (77.0, 86.5, 61.5%) (Sexton et al. 2016; Reinarman et al. 2011; Reiman 2007). This is substantiated by the fact that Caucasians are the racial majority in the US, particularly in the states where the clinics are located.

The median estimated household income in the ZIP codes where our patient sample resides was higher than the US median, $69,481 compared to $61,937 (Bureau UC 2019). When taking into consideration the median household income from just the included states, $58,912 (US Income Statistics - Current Census Data for Zip Codes 2018), the median estimated household income from our sample was still higher; however, as the income data for our sample was a surrogate, this may be inflated and potentially inaccurate. Similar studies tend to report that income among medical cannabis users is lower than the average, which highlights the need for additional investigation (Sexton et al. 2016; Reiman 2007).

Data collected as part of the intake for patients in this retrospective study provide an interesting perspective on cannabis experience prior to seeking medical certification, as almost 70% reported using cannabis prior to their certification. This number is substantially higher than the lifetime cannabis use estimate among Americans from the National Survey on Drug Use and Health, which reported a lifetime cannabis use of 45.3% in 2018 (2018 NSDUH Detailed Tables | CBHSQ Data 2019). Unfortunately, it is not known how many of the patients in the dataset had medical certification from a separate clinic or physician elsewhere prior to becoming a patient at a CB2 Insights clinic.

Strengths of this study include the large sample of patients accessing medical cannabis across 12 states. The consistent input of data at the clinics allowed for a comprehensive review of characteristics, and most importantly, provided data on all medical conditions for which patients sought medical cannabis, rather than just one per patient. Additionally, data collection was verified by medical professionals at the time of input. Limitations of this study primarily include missing data (i.e., a large number of patients for whom gender and race were not reported), a lack of ethnicity data, the absence of data on patients who did not qualify for medical cannabis certification and were not included in the registry, and the use of surrogate income data. Another limitation is that the data came from a single network of clinics, and do not represent patients in all states where medical cannabis is legal.