Cannabidiol use and effectiveness: real-world evidence from a Canadian medical cannabis clinic Open Access This article is licensed under a Creative Commons Attribution 4.0 International Cannabidiol (CBD) is an active ingredient in cannabis that is derived from the hemp plant, but it does not cause a high and is not addictive. CBD has been shown to be effective in treating conditions like pain, insomnia, and anxiety. Cannabidiol in Anxiety and Sleep: A Large Case Series Cannabidiol (CBD) is one of many cannabinoid compounds found in cannabis. It does not appear to alter consciousness or trigger a “high.” A
Cannabidiol use and effectiveness: real-world evidence from a Canadian medical cannabis clinic
Open AccessThis article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/.
The datasets used and/or analyzed during the current study are available from the corresponding author on reasonable request.
Cannabidiol (CBD) is a primary component in the cannabis plant; however, in recent years, interest in CBD treatments has outpaced scientific research and regulatory advancement resulting in a confusing landscape of misinformation and unsubstantiated health claims. Within the limited results from randomized controlled trials, and lack of trust in product quality and known clinical guidelines and dosages, real-world evidence (RWE) from countries with robust regulatory frameworks may fill a critical need for patients and healthcare professionals. Despite growing evidence and interest, no real-world data (RWD) studies have yet investigated patients’ reports of CBD impact on symptom control in the common expression of pain, anxiety, depression, and poor wellbeing. The objective of this study is to assess the impact of CBD-rich treatment on symptom burden, as measured with a specific symptom assessment scale (ESAS-r).
This retrospective observational study examined pain, anxiety, depression symptoms, and wellbeing in 279 participants over 18 years old, prescribed with CBD-rich treatment at a network of clinics dedicated to medical cannabis in Quebec, Canada. Data were collected at baseline, 3 (FUP1), and 6 (FUP2) month after treatment initiation. Groups were formed based on symptom severity (mild vs moderate/severe) and based on changes to treatment plan at FUP1 (CBD vs THC:CBD). Two-way mixed ANOVAs were used to assess ESAS-r scores differences between groups and between visits.
This retrospective observational study suggests CBD-rich treatment has a beneficial impact on pain, anxiety, and depression symptoms as well as overall wellbeing only for patients with moderate to severe symptoms; however, no observed effect on mild symptoms. The results of this study contribute to address the myths and misinformation about CBD treatment and demand further investigation.
Cannabidiol (CBD) is one of the primary cannabinoids found in significant but variable concentrations in cannabinoid-based medicines (CBM). While structurally similar to Δ9-tetrahydrocannabinol (THC), CBD does not cause intoxication or euphoria (Russo 2017) and has showed considerable tolerability in humans with a low abuse potential (Chesney et al. 2020). This favorable safety profile has led to the recent mitigation of legal and regulatory barriers surrounding purified CBD products in several countries and recent increased interest in CBD treatments. While recent rulings clarified that CBD is not a drug under the 1961 United Nations as Single Convention on Narcotic Drugs, regulatory status in the USA remains extremely confusing. When derived from cannabis, CBD is a schedule 1 drug but when derived from “industrial hemp” plants it may be lawful federally (Corroon and Kight 2018; Corroon et al. 2020). In Canada, CBD is controlled under the Cannabis Act as are all cannabinoids, cannabis, and cannabis-derived products (Canada Go 2021). This regulatory status imparts restrictions and access obstacles for researchers.
CBD is widely touted as a panacea for a wide range of health problems and has been marketed as a dietary and “wellness” product (Russo 2017; Khalsa et al. 2020; Eisenstein 2019). CBD’s potential effects as an add-on therapy have been studied for social anxiety disorders, schizophrenia, non-motor symptoms in Parkinson’s disease, and substance use disorders (Bergamaschi et al. 2011; Crippa et al. 2019; McGuire et al. 2018; Millar et al. 2019; Prud’homme et al. 2015; Thiele et al. 2019; Leehey et al. 2020). However, the evidence of its effectiveness for indications other than drug-resistant pediatric epilepsy conditions remains very limited (Larsen and Shahinas 2020; Franco et al. 2020) and safety considerations such as drug-drug interactions associated with unsupervised use remain (Chesney et al. 2020; Freeman et al. 2019). Randomized controlled trials (RCTs) are limited in their rigorous design, population sample, and duration of observation making generalization of results and long-term data scarce. Therefore, real-world evidence (RWE) provides valuable insights and supplemental information about the use, safety, and effectiveness of CBD-based treatments (Graham et al. 2020).
RWE from retrospective analyses and patient registries shows that CBMs are used for pain (chronic, neuropathic), mental health conditions, cancer-related symptoms (nausea, fatigue, weakness), HIV/AIDS, and neurological conditions (Bonn-Miller et al. 2014; Gulbransen et al. 2020; Lintzeris et al. 2020; Lucas and Walsh 2017; Sexton et al. 2016; Waissengrin et al. 2015). Symptom control is the primary reason for use of CBM, with most patients looking to address unalleviated symptoms, perceived symptom intensity, and burden on health-related quality of life independently of primary diagnosis (Sexton et al. 2016; Waissengrin et al. 2015; Baron et al. 2018; Purcell et al. 2019; Swift et al. 2005; Webb and Webb 2014). The Edmonton Symptom Assessment Scale-revised version (ESAS-r) is a validated scale to assess symptom burden developed for use in oncology and palliative care (Hui and Bruera 2017), it has relevance to medical cannabis care as patients are often treated for similar symptom management (Good et al. 2019; Pawasarat et al. 2020). Specifically, studies showed self-perceived improvement in ESAS-r emotional symptoms (anxiety and depression) scores following CBM treatment in oncology patients, while pain and wellbeing symptoms showed no improvement (Good et al. 2019; Pawasarat et al. 2020). Yet, RWE on CBD-rich products is scarce (Goodman et al. 2020; Shannon et al. 2019). In addition, although careful titration and treatment adjustment after initiation is critical to symptom improvement and adverse effects care, current literature has failed to address this issue.
In this study, we investigated treatment with CBD-rich products within a dedicated clinical setting in Quebec, Canada, and the effects on a very common clinical symptom expression of pain and comorbid anxiety and depression symptoms, as well as the effect on overall wellbeing. We also examined the relevant clinical effects that were observed when CBD-rich treatments were replaced by THC:CBD-balanced products at subsequent follow-up visits.
This study is a retrospective examination of patients who were prescribed CBD-rich products by physicians at a clinic dedicated to CBM treatments operating at four locations across Quebec, Canada. All data are collected as part of standard clinical procedures during the initial visit and during 3 (FUP1) and 6 (FUP2) month follow-up visits and extracted from electronic medical records (EMR) (Prosk et al., 2021). All data were anonymized following extraction from the EMR and no identifiers linking to original data were maintained. A waiver of consent was required and approved by Advarra Ethics Committee, who also approved the study protocol, and by the provincial privacy commission (La commission d’accès à l’information du Quebec).
Adult patients, at least 18 years of age, who were initially treated exclusively with CBD-rich products from 1 October 2017 to 31 May 2019 and for whom outcome scores and product information were recorded at FUP1 were included in this study. Patients were generally referred by primary-care physicians and specialists for an assessment on the suitability of medical cannabis to treat refractory symptoms. A complete medical history, including primary and secondary diagnoses, was collected at baseline visit. Medical cannabis treatment decisions are determined at the discretion of a clinic physician according to a standardized clinical procedure, including symptom identification, selection of product format, cannabinoid profile, and dosage based on existing evidence (MacCallum and Russo 2018; Cyr et al. 2018), but also to minimize risk of adverse effects. Patient and physician preference may also indicate initiation with products that have higher CBD and lower THC concentration in order to limit use of THC and its inherent potential adverse events. The follow-up visits serve to assess treatment compliance, safety, and effectiveness.
CBD-rich products in Canada
CBD-rich products are administered in various methods and formats, but most commonly as oral plant-derived extracts or oils and as inhaled dried flowers. In the Canadian medical cannabis program, CBD-rich cannabis oils contain approximately 0.5–1 mg of THC/mL and 20–25 mg of CBD/mL depending on the product manufacturer. Table Table1 1 provides cannabinoid content and THC:CBD ratio for the three most common oil products (over 85% of patients) authorized at the clinic. Furthermore, product details in this study sample are described in Table Table3. 3 . The clinic procedure dictates that all products with a ratio of CBD (mg) to THC (mg) higher than 10 are considered CBD-rich products.
THC and CBD contents and associated THC:CBD ratio for the three most common oil products authorized at the clinic
|CBD-rich products at baseline||THC:CBD-balanced products at FUP1||THC-rich products at FUP1|
|Authorized dose range (in ml/intake)||0.1–2||0.05–3||0.2–1.5|
|Oil (mg/ml)||THC||CBD||Ratio THC:CBD||THC||CBD||Ratio THC:CBD||THC||CBD||Ratio THC:CBD|
|Product 1||1.2||24||1:25||9.5||12||10:13||27.5||< 1||30:1|
|Product 3||< 1||20||1:20||10||13.5||10:13||26.3||< 1||30:1|
The data is categorized by product category: CBD-rich products, THC:CBD-balanced products, and THC-rich products
CBD cannabidiol, THC Δ9-tetrahydrocannabinol, SD standard deviation
Details of the THC and CBD component of the CBD-rich, the THC:CBD 1:1, and the THC-rich formulations
|CBD-rich products at baseline (n = 279)||THC:CBD-balanced products at FUP1 (n = 104)||THC-rich products at FUP1 (n = 12)|
|Oil products (in mg/ml)||0.1–2.0||2.0–52.0||0.6–30||2.5–39||1.25–45||0–18|
|Dried flower (in % w/w)||0.7||17.0||3.7–9||7.7–13.4||13–27||0–0.5|
|Average daily dose (mg)||0.5||11.47||19.65||26.32||54.28||10.80|
|Standard deviation (mg)||0.43||10.21||5.80||9.12||29.65||7.64|
|Maximum daily dose (mg)||6||156||60||78||90||54|
Data comes from our sample of 279 patients
CBD cannabidiol, THC Δ9-tetrahydrocannabinol
Treatment adjustments occur at follow-up visits as a result of lack of effectiveness, presentation of adverse effects, or social or economic barriers. Adjustments may include a change of the recommended CBD-rich product, method of administration, dosage, or a change in product formulation such as the introduction of THC:CBD-balanced or THC-rich products. We investigated the change from CBD-rich to THC:CBD products during FUP1 by forming two groups based on their product adjustment at FUP1 (CBD-rich vs THC:CBD). Products at FUP1 reflect those recommended at the visit. Therefore, the adjusted treatment affects only the evaluation at FUP2.
Patients age, sex, and diagnosis were recorded at baseline. Patients completed the ESAS-r (Edmonton Symptom Assessment System-revised version) at each visit. The ESAS-r is a self-administered scale, rating the severity of symptoms from 0 (absence of symptom) to 10 (worst possible severity) at the time of assessment (Hui and Bruera 2017). Symptoms evaluated include six physical- (pain, tiredness, nausea, drowsiness, lack of appetite, and shortness of breath), two emotional- (depression, anxiety), and one overall wellbeing-related symptoms. ESAS scores can be categorized as mild (score 0 to 3) moderate (score 4 to 6) or high (score 7 and above) (Butt et al. 2008) and the threshold for clinically significant improvement is a decrease of 1 point (Hui et al. 2015). Since pain and mental health issues represent the most common symptoms for patients and physicians seeking medical cannabis treatments, we investigated effects on pain, depression, and anxiety symptoms as well as overall wellbeing. For each symptom, two groups of patients were formed: moderate-severe severity group in which a baseline score of 4 or more was recorded and a mild severity group with baseline score of 0 to 3.
Mean scores and standard deviation (SD), as well as percentage, where appropriate are presented for each variable. All analyses were performed on each ESAS-r symptom separately through the data analytics software R v4.0.2. An initial analysis compared the overall ESAS-r scores between each visit no matter the severity of the group, and looked at the role of product group (CBD/THC:CBD vs CBD/CBD group) (between-factor). Tukey HSD post hoc test was used to confirm where the differences occurred between groups.
To determine whether CBD-based treatments have different effectiveness based on the severity of patient symptoms, two-way mixed ANOVAs with severity group as between-factor and visit as a within-factor were conducted to assess the change in ESAS-r scores between visits. Paired t-tests were subsequently performed to assess the difference in mean scores within each severity group between baseline and FUP1. Significant p value was set at 0.05 and all analyses were two-tailed. Partial eta-squared (η 2 p) are reported to indicate magnitude of differences between groups.
A total of 1095 patients were seen at the four clinic sites during the study period. Out of those, 715 were eligible for the study (at least 18 years old and initially treated exclusively with CBD-rich products). A total of 279 patients with ESAS-r scores and product information at FUP1 were analyzed (190 (68%) female, mean age = 61.1, SD = 16.6). The analyzed sample did not differ from the study-eligible group in terms of age, sex, or THC and CBD initial doses (all ps > 0.4). Table Table2 2 outlines patient sample size and demographic information for each symptom and treatment group. Two hundred and ten (75%) patients were prescribed CBD-rich products to treat chronic pain, 19 (7%) for cancer-related symptoms, 21 (7.5%) to treat neurological disorders (Parkinson’s disease, multiple sclerosis, and drug-resistant epilepsy among others), 8 patients for inflammatory disease (arthritis), 10 for gastrointestinal disorders (Chron’s disease, inflammatory bowel syndrome, ulcerative colitis), 2 for anxiety, 1 for depression, 2 for headaches, and 6 unclassified. The chronic pain category included all medical indications for which pain was the main symptom such as but not limited to fibromyalgia, spinal stenosis, and chronic low back pain. Overall, 116 (41.6%) patients adjusted their prescription by adding THC at FUP1 (either to a THC:CBD-balanced combination or a THC-rich treatment). Two hundred and three (73%) patients had moderate/severe ESAS-r scores on at least 2 of the examined symptoms, 57 (20%) on three, and 75 (27%) on all four symptoms. Twenty-nine (10%) patients report no moderate/severe symptoms; these people may use CBD for other ESAS-r symptoms not examined here (shortness of breath, tiredness, nausea, drowsiness, appetite). There was no statistical difference on either age, sex, or THC and CBD initial doses between the patients who completed one FUP versus those who completed two FUP (all ps > 0.1).
Demographic characteristics of 279 medical cannabis patients, by symptom group
|Sample size (percentage)||Number of female patients (percentage)||Mean age (SD)|
|Overall sample||279||190 (68)||61.1 (16.6)|
|Moderate or severe pain symptom group||205 (73.5)||150 (73)||61.8 (15.9)|
|Moderate or severe anxiety symptom group||138 (48.5)||97 (70)||61.43 (16.3)|
|Moderate or severe depression symptom group||115 (41.2)||81 (70)||60.5 (15)|
|Moderate or severe wellbeing group||202 (72.4)||141 (70)||60.8 (16.1)|
|CBD/THC:CBD group||116 (41.6)||75 (65)||60.38 (14.4)|
The symptom groups are mild and moderate or severe. The table presents the moderate or severe demographic characteristics. The CBD/THC:CBD group is composed of patients who added THC to their CBD-rich prescription during FUP1
CBD cannabidiol, THC Δ9-tetrahydrocannabinol, SD standard deviation
CBD-rich products characteristics
The baseline average daily doses for CBD and THC are presented in Table Table3. 3 . The maximum initial CBD dose recorded (156 mg) was prescribed for the treatment of pain of one patient. The maximum THC dose recorded at FUP1 (90 mg) was prescribed for two patients for the treatment of pain.
Outcome of CBD treatment
Mean ESAS-r scores of pain, anxiety, depression symptoms, and overall wellbeing at baseline, FUP1, and FUP2 are described in Table Table4 4 and Fig. Fig.1 1 .
Mean and standard deviation (SD) scores of ESAS-r scales for each severity group (mild or moderate/severe) and for each product group (CBD/CBD or CBD/THC:CBD)
|Baseline (sample size)||277||270||272||268|
|Overall sample||5.14 (2.57)||3.86 (3.19)||3.16 (3.08)||5.34 (2.61)|
|Mild severity group||1.69 (1.1)||0.99 (1.15)||0.87 (1.18)||1.86 (1.18)|
|Moderate or severe severity group||6.34 (1.7)||6.61 (1.78)||6.3 (1.86)||6.47 (1.83)|
|CBD/CBD group||5.03 (2.66)||3.80 (3.21)||2.99 (3.04)||5.28 (2.72)|
|CBD/THC:CBD group||5.28 (2.45)||3.95 (3.17)||3.40 (3.13)||5.42 (2.46)|
|FUP1 (sample size)||262||261||261||254|
|Overall Sample||4.37 (2.73)||2.93 (2.95)||2.33 (2.79)||4.45 (2.6)|
|Mild severity group||2.3 (2.4)||1.62 (2.08)||1.12 (1.78)||3.73 (2.75)|
|Moderate or severe severity group||5.04 (2.49)||4.15 (3.09)||3.77 (3.07)||4.72 (2.5)|
|CBD/CBD group||4.09 (2.67)||2.74 (2.87)||2.23 (2.71)||4.43 (2.6)|
|CBD/THC:CBD group||4.75 (2.78)||3.2 (3.05)||2.47 (2.9)||4.49 (2.63)|
|FUP2 (sample size)||101||99||102||97|
|Overall Sample||4.7 (2.7)||2.85 (3.01)||2.67 (3.02)||4.57 (2.47)|
|Mild severity group||2.18 (2.43)||1.32 (1.89)||1.52 (2.31)||3.82 (2.81)|
|Moderate or severe severity group||5.2 (2.47)||3.96 (3.19)||3.74 (3.26)||4.93 (2.23)|
|CBD/CBD group||4.55 (2.6)||2.44 (2.68)||2.44 (2.82)||4.76 (2.22)|
|CBD/THC:CBD group||4.88 (2.81)||3.08 (3.07)||2.94 (3.24)||4.36 (2.73)|
The CBD/THC:CBD group is composed of patients who added THC to their CBD-rich prescription during FUP1. ESAS-r scores varied between 0 and 10 for all assessed symptoms and all visits except for the anxiety scale at FUP2 for which the maximum score was 9
CBD cannabidiol, FUP1 follow-up visit at 3 month, FUP2 follow-up visit at 6 month, THC Δ9-tetrahydrocannabinol
CBD-rich treatment effectiveness on pain, anxiety, depression symptoms, and on overall wellbeing in 279 patients. FUP1, follow-up visit at 3 month; FUP2, follow-up visit at 6 month. Mixed ANOVAs revealed a significant effect of visit on symptom reduction between baseline and FUP1 but not between FUP1 and FUP2
All average ESAS-r scores decreased between baseline and FUP1 and FUP2. This was further demonstrated by ANOVAs which revealed a significant effect of visit on mean ESAS-r scores for each symptom assessed (pain: F(2,634) = 4.9, p < 0.008; anxiety: F(2,624) = 8.36, p < 0.001, depression: F(2,629) = 5.36, p < 0.004; wellbeing: F(2,613) = 8.31, p < 0.001; all η 2 p between 0.008 and 0.02). In all assessed symptoms, no significant main effect of adding THC at FUP1, nor visit-by-product interaction, were observed (all ps > 0.2). Post hoc tests revealed ESAS-r mean scores significantly decreased between baseline and FUP1 (all ps < 0.003) for all symptoms, between baseline and FUP2 for anxiety and wellbeing (both ps < 0.03), but not between FUP1 and FUP2 for any symptoms (all ps >0.5). This suggests statistical improvement recorded at FUP1 is still present at FUP2 in all symptoms independently from treatment adjustment at FUP1.
CBD treatment impact according to symptom severity
From Table Table2, 2 , moderate or severe scores at baseline were most common for pain (205 patients, 73.5%) and poor wellbeing (202 patients, 72.4%).
Clinical effect (difference of 1.3 to 2.5 points) observed in all symptoms for patients with moderate/severe symptoms between baseline and FUP1; however, there was no clinical effect for patients with mild symptoms (from − 0.3 to − 1.8) (Fig. (Fig.2). 2 ). No clinical effect was observed in any symptoms between FUP1 and FUP2 for patients with moderate/severe symptoms (− 0.4 to 0.5) as well as for patients with mild symptoms (from − 0.7 to 0.4).
CBD-rich treatment effect according to symptom severity: mild or moderate/severe in 279 patients. FUP1, follow-up visit at 3 month; FUP2, follow-up visit at 6 month. a Mean ESAS-r scores for the pain symptom, b mean ESAS-r scores for the anxiety symptom, c mean ESAS-r scores for the depression symptom, and d mean ESAS-r scores for overall wellbeing. According to mixed ANOVAs, patients with moderate/severe symptoms reported symptom reduction whereas patients with mild symptoms reported symptom deterioration from baseline to FUP1. No effect was statistically significant between FUP1 and FUP2
The ANOVA revealed that all main and interaction effects were significant at the 0.001 level with effect sizes large for severity (η 2 p = 0.29), medium for visit (η 2 p = 0.06), and small for the interaction (η 2 p = 0.03). Post hoc tests revealed a significant score difference between baseline and FUP1 and FUP2 (both ps < 0.05) but not between FUP1 and FUP2 (p = 0.98). Patients with moderate/severe symptoms on pain experienced important improvement at FUP1 (t(194) = 7.61, p < 0.001) whereas ESAS-r scores for patients with mild symptoms actually increased (t(64) = − 2.03, p < 0.05) (Fig. (Fig.2 2 a).
There were significant effects of visit, severity group, and visit by group interaction (all ps < 0.001; η 2 p = 0.006, η 2 p = 0.4, η 2 p = 0.1, respectively). Post hoc tests revealed a significant score difference between baseline and FUP1 and FUP2 (both ps < 0.001) but not between FUP1 and FUP2 (p = 0.38). Although there was a large improvement for patients with moderate to severe anxiety symptoms (t(131) = 9.36, p < 0.001), the anxiety scores of patients with mild symptoms increased (t(119) = − 3.19, p < 0.01) from baseline to FUP1 (Fig. (Fig.2 2 b).
The ANOVA showed main effects of visit, severity group (both ps < 0.001 with η 2 p = 0.04 and η 2 p = 0.4, respectively) and a significant group-by-visit interaction (F(2,620) = 34.47, p < 0.001; η 2 p = 0.1). Post hoc tests revealed a significant score difference between baseline and FUP1 and FUP2 (both ps < 0.01) but not between FUP1 and FUP2 (p = 0.85). Specifically, the scores of moderate/severe group decreased notably (t(110) = 9.56, p < 0.001) between baseline and FUP1 but the scores of the group with mild depression symptoms did not (p = 0.07) (Fig. (Fig.2 2 c).
The ANOVA showed main effects of visit, severity group (both ps < 0.001 with η 2 p =0.04 and η 2 p =0.3 respectively) and a significant group-by-visit interaction (F(2,597) = 36.53, p < 0.001; η 2 p = 0.11). Post hoc tests revealed a significant main score difference between baseline and FUP1 and FUP2 (both ps < 0.01) but not between FUP1 and FUP2 (p = 0.89). Precisely, the scores of the group reporting good wellbeing increased (t(182) = 8.8, p < 0.001) whereas scores of patients with worst wellbeing notably decreased (t(59) = − 5.08, p < 0.001) between FUP1 and FUP2 (Fig. (Fig.2 2 d).
This retrospective study explored the use of CBD-rich products in a medical cannabis clinical setting in Canada and associated effectiveness on a common symptom cluster presentation of pain, anxiety, depression, and poor sense of wellbeing, as measured by ESAS-r.
Patients treated with CBD-rich products were mainly women in their sixties, seeking predominantly chronic pain management.
Our findings show that overall effectiveness of CBD treatment is primarily by patients with moderate to severe symptoms. A deficiency in the endocannabinoid system (ECS) may provide a possible explanation for this result (Russo 2016). The ECS could be more deficient in patients with moderate/severe symptoms compared to mild symptoms leading to increased improvement in the first group. The absence of significant improvement for patients with mild symptoms at baseline may be explained by a smaller margin for symptom improvement. In such patients, CBD treatments may have been targeted to other clinical symptoms not assessed in the current study. There is a probable placebo effect; however, there were no differences in initial CBD doses between the severity groups. Furthermore, associated placebo effect would likely be decreased by FUP3M, also considering the significant treatment cost. The distinct beneficial impact of CBD treatment observed for patients with moderate-severe symptoms could elucidate discrepancies found in the literature.
RCTs on CBM and pain symptoms provide inconclusive results; however, several report that treatments of THC and CBD have some benefit for pain management (Häuser et al. 2018; Russo 2008; Prosk et al. 2020). Our results are largely novel as research on the effect of CBD on pain control is very limited (Boyaji et al. 2020). The reduction in reported anxiety may also contribute to the improvement in pain perception.
Discrepancies still exist regarding the anxiolytic effect of CBD. Some RCTs indicate an anxiolytic effect of CBD upon experimentally induced scenarios (Bergamaschi et al. 2011; Zuardi et al. 2017; Bhattacharyya et al. 2010; Skelley et al. 2020); however, these findings are difficult to replicate (Larsen and Shahinas 2020; Hundal et al. 2018; Crippa et al. 2012). This reinforces our findings that CBD may have a differential effect depending on anxiety severity. Regarding the effects of CBD on depression symptoms, further research is required to draw conclusions (Khalsa et al. 2020; Schier et al. 2014; Turna et al. 2017).
The addition of THC to CBD during FUP1 did not produce any effect on ESAS-r scores at FUP2 in this analysis; however, the magnitude of the difference between groups is small. The examination of treatment regimen has been seldom addressed in the literature and further development is required to inform guidelines for prescription and refinement of clinical practice.
Furthermore, a significant discrepancy is observed between the recorded dosages of oral CBD in RCTs and dosages in real-world settings. The average daily CBD dosage authorized at our clinic (11.5 mg) is closer to other observational studies (Gulbransen et al. 2020) compared to what is seen in RCTs (up to 1000 mg for a single dose) (Larsen and Shahinas 2020). The presence of THC and other cannabinoids in CBD-rich products may affect the outcomes in this study. The majority of RCTs investigated single-dose administration of CBD making it difficult to compare observed treatment outcomes with chronic dosing clinical settings. Importantly, medical cannabis products are generally not covered by most insurers and patients rely on out-of-pocket payments. The cost of CBD remains very high globally, approximately $CAD 5–20 per 100 mg (Canada Go 2021; Eisenstein 2019; Canada 2020). Availability of reliable cannabinoid testing in certain international jurisdictions is also limited. The gap between effective doses demonstrated in RCTs and the actual affordable doses demonstrated by RWE mandate the need for a precise pricing and marketing strategy at the initiation of any drug development process.
Limitations are common in real-world data (RWD), especially in retrospective studies. In this study, with no control group, no causality effect can be drawn between CBD-rich treatment and symptom improvement. Most patients treated with CBM present with multiple severe symptoms and the analyses presented here are limited to identify the treatment outcomes for such patients. Further studies can investigate the use of CBD to treat several symptoms simultaneously.
The self-reported subjective assessment used may be biased by the patient’s positive expectation of treatment, which could lead to a possible placebo effect. This perceived effectiveness bias may also be increased by social and economic barriers. The current context of medical cannabis access, including social stigma, high cost, and lack of universal insurance coverage can increase the patient selection bias. Self-selection bias is increased by the significant patient interest in medical cannabis as these patients must be motivated to access the non-traditional medication system. This bias limits the generalizability of results but is common across international medical cannabis regimens and should not discount the observed results. The heterogeneity of the patient population with a variety of diagnoses and the diversity of medical cannabis preparations also affects the external validity of the study. However, clinical findings from within Canada’s controlled regulatory program do provide important models for international consideration. Future research is required in controlled clinical settings to examine these factors in order to provide a more complete account of CBD effectiveness.
Also, there was a large drop of sample size (53% loss) due to missing data. Additionally, there was an important loss to follow-up at the 6-month visit (FUP2) due to missed appointment and cost barriers, limiting the power of the findings. The total treatment cost has significant impact on treatment continuation. Improved patient retention and more robust, harmonized data collection methods will improve future observational studies and allow for long-term assessment. Collection of detailed, accurate product information is a challenge, especially with inhaled products (Corroon et al. 2020). There are opportunities for administration devices and other technology advancements to improve this limitation. Lastly, this study did not include safety data assessment, future studies should investigate safety considerations of CBD (Chesney et al. 2020). Collection of high-quality RWD will require improvements in patient retention, data monitoring, and more robust data collection methods within a controlled clinical setting.
This study on CBD-rich products demonstrates the potential of RWE for the advancement of medical cannabis research and practice guidelines, especially in a world where CBD use is exponentially increasing but scientific data are limited. It revealed that CBD-rich treatments have a beneficial impact on patients with self-reported moderate or severe symptoms of pain, anxiety, or depression and overall wellbeing but not in patients with mild symptoms. Further investigation is clearly required, but as of now the hyped, and often illegal, marketed claims of CBD as a wellness product are unsubstantiated. Our findings have important and novel implications to clinical practice, especially the examination of treatment plan adjustment during the first follow-up after initiation with CBD treatments. Improvements in access regimes, oversight, and clarification from regulatory agencies are also needed to improve the validity of RWE and assessment of the use of CBD-rich products.
The authors would like to thank the participants to this study. The authors would like to acknowledge Santé Cannabis co-founder Dr. Michael Dworkind and key clinical leaders Dr. Antonio Vigano, Dr. Howard Mitnick, Dr. Alain Watier, and Youri Drozd, clinical data assistant, for his contribution to data technical help.
|EMR||Electronic medical record|
|ESAS-r||Edmonton Symptom Assessment System-revised version|
All authors contributed to conception and design, interpretation of data, manuscript writing, and final approval. LR and RG conducted the analysis of data. All authors agreed to be accountable for their own contributions. The author(s) read and approved the final manuscript.
This research was funded internally by Santé Cannabis clinic.
Availability of data and materials
The datasets used and/or analyzed during the current study are available from the corresponding author on reasonable request.
A waiver of consent was required and approved by Advarra Ethics Committee, who also approved the study protocol, and by the provincial privacy commission (La commission d’accès à l’information du Quebec).
L.R.: Clinical research associate, employee at Santé Cannabis.
R.G.: Epidemiologic and statistic consultant for Santé Cannabis.
C.EH.: Director of Research and Innovation, employee at Santé Cannabis.
MF.A.: Associate Research Director of Santé Cannabis.
E.P.: President and co-founder of Santé Cannabis.
Santé Cannabis is a medical clinic, research, and training center dedicated to medical cannabis. The views expressed are those of the authors. This is a retrospective, observational study which took place at Santé Cannabis; therefore, the design and conduct of the study was executed by Santé Cannabis clinic staff. C.EH. and E.P. had a supporting role, in the retrospective protocol development. The authors had no role in the conduct of the study and collection of data. None of the authors are involved in the care of patients or in treatment decisions. The authors acted independently, and Santé Cannabis had no role in the analysis of the study, nor the writing of the manuscript or decision to publish. There is no financial gain for Santé Cannabis or for the authors to publish. The authors, while connected to Santé Cannabis, do not have a financial or professional incentive for the decision to publish.
Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
Cannabidiol (CBD): What we know and what we don’t
Cannabidiol (CBD) is often covered in the media, and you may see it touted as an add-in booster to your post-workout smoothie or morning coffee. You can even buy a CBD-infused sports bra. But what exactly is CBD? And why is it so popular?
How is cannabidiol different from marijuana, cannabis and hemp?
CBD, or cannabidiol, is the second most prevalent active ingredient in cannabis (marijuana). While CBD is an essential component of medical marijuana, it is derived directly from the hemp plant, a cousin of marijuana, or manufactured in a laboratory. One of hundreds of components in marijuana, CBD does not cause a “high” by itself. According to a report from the World Health Organization, “In humans, CBD exhibits no effects indicative of any abuse or dependence potential…. To date, there is no evidence of public health related problems associated with the use of pure CBD.”
Is cannabidiol legal?
CBD is readily obtainable in most parts of the United States, though its exact legal status has been in flux. All 50 states have laws legalizing CBD with varying degrees of restriction. In December 2015, the FDA eased the regulatory requirements to allow researchers to conduct CBD trials. In 2018, the Farm Bill made hemp legal in the United States, making it virtually impossible to keep CBD illegal – that would be like making oranges legal, but keeping orange juice illegal.
The Farm Bill removed all hemp-derived products, including CBD, from the Controlled Substances Act, which criminalizes the possession of drugs. In essence, this means that CBD is legal if it comes from hemp, but not if it comes from cannabis (marijuana) – even though it is the exact same molecule. Currently, many people obtain CBD online without a medical marijuana license, which is legal in most states.
The evidence for cannabidiol health benefits
CBD has been touted for a wide variety of health issues, but the strongest scientific evidence is for its effectiveness in treating some of the cruelest childhood epilepsy syndromes, such as Dravet syndrome and Lennox-Gastaut syndrome (LGS), which typically don’t respond to antiseizure medications. In numerous studies, CBD was able to reduce the number of seizures, and, in some cases, stop them altogether. Epidiolex, which contains CBD, is the first cannabis-derived medicine approved by the FDA for these conditions.
Animal studies, and self-reports or research in humans, suggest CBD may also help with:
Studies and clinical trials are exploring the common report that CBD can reduce anxiety.
- Insomnia. Studies suggest that CBD may help with both falling asleep and staying asleep.
- Chronic pain. Further human studies are needed to substantiate claims that CBD helps control pain. One animal study from the European Journal of Pain suggests CBD could help lower pain and inflammation due to arthritis when applied to skin. Other research identifies how CBD may inhibit inflammatory and neuropathic pain, which are difficult treat.
- Addiction. CBD can help lower cravings for tobacco and heroin under certain conditions, according to some research in humans. Animal models of addiction suggest it may also help lessen cravings for alcohol, cannabis, opiates, and stimulants.
Is CBD safe?
Side effects of CBD include nausea, fatigue and irritability. CBD can increase the level of blood thinning and other medicines in your blood by competing for the liver enzymes that break down these drugs. Grapefruit has a similar effect with certain medicines.
People taking high doses of CBD may show abnormalities in liver related blood tests. Many non-prescription drugs, such as acetaminophen (Tylenol), have this same effect. So, you should let your doctor know if you are regularly using CBD.
A significant safety concern with CBD is that it is primarily marketed and sold as a supplement, not a medication. Currently, the FDA does not regulate the safety and purity of dietary supplements. So, you cannot be sure that the product you buy has active ingredients at the dose listed on the label. In addition, the product may contain other unknown elements. We also don’t know the most effective therapeutic dose of CBD for any particular medical condition.
How can CBD be taken?
CBD comes in many forms, including oils, extracts, capsules, patches, vapes, and topical preparations for use on skin. If you’re hoping to reduce inflammation and relieve muscle and joint pain, a topical CBD-infused oil, lotion or cream – or even a bath bomb — may be the best option. Alternatively, a CBC patch or a tincture or spray designed to be placed under the tongue allows CBD to directly enter the bloodstream.
Outside of the US, the prescription drug Sativex, which uses CBD as an active ingredient, is approved for muscle spasticity associated with multiple sclerosis and for cancer pain. Within the US, Epidiolex is approved for certain types of epilepsy and tuberous sclerosis.
The bottom line on cannabidiol
Some CBD manufacturers have come under government scrutiny for wild, indefensible claims, such that CBD is a cure-all for cancer or COVID-19, which it is not. We need more research but CBD may prove to be a helpful, relatively non-toxic option for managing anxiety, insomnia, and chronic pain. Without sufficient high-quality evidence in human studies, we can’t pinpoint effective doses, and because CBD currently is typically available as an unregulated supplement, it’s hard to know exactly what you are getting.
If you decide to try CBD, make sure you are getting it from a reputable source. And talk with your doctor to make sure that it won’t affect any other medicines you take.
Cannabidiol in Anxiety and Sleep: A Large Case Series
Cannabidiol (CBD) is one of many cannabinoid compounds found in cannabis. It does not appear to alter consciousness or trigger a “high.” A recent surge in scientific publications has found preclinical and clinical evidence documenting value for CBD in some neuropsychiatric disorders, including epilepsy, anxiety, and schizophrenia. Evidence points toward a calming effect for CBD in the central nervous system. Interest in CBD as a treatment of a wide range of disorders has exploded, yet few clinical studies of CBD exist in the psychiatric literature.
To determine whether CBD helps improve sleep and/or anxiety in a clinical population.
A large retrospective case series at a psychiatric clinic involving clinical application of CBD for anxiety and sleep complaints as an adjunct to usual treatment. The retrospective chart review included monthly documentation of anxiety and sleep quality in 103 adult patients.
Main Outcome Measures
Sleep and anxiety scores, using validated instruments, at baseline and after CBD treatment.
The final sample consisted of 72 adults presenting with primary concerns of anxiety (n = 47) or poor sleep (n = 25). Anxiety scores decreased within the first month in 57 patients (79.2%) and remained decreased during the study duration. Sleep scores improved within the first month in 48 patients (66.7%) but fluctuated over time. In this chart review, CBD was well tolerated in all but 3 patients.
Cannabidiol may hold benefit for anxiety-related disorders. Controlled clinical studies are needed.
The Cannabis plant has been cultivated and used for its medicinal and industrial benefits dating back to ancient times. Cannabis sativa and Cannabis indica are the 2 main species.1 The Cannabis plant contains more than 80 different chemicals known as cannabinoids. The most abundant cannabinoid, tetrahydrocannabinol (THC), is well known for its psychoactive properties, whereas cannabidiol (CBD) is the second-most abundant and is nonpsychoactive. Different strains of the plant are grown containing varying amounts of THC and CBD. Hemp plants are grown for their fibers and high levels of CBD that can be extracted to make oil, but marijuana plants grown for recreational use have higher concentrations of THC compared with CBD.2 Industrial hemp must contain less than 0.3% THC to be considered legal, and it is from this plant that CBD oil is extracted.3
Many different cultures have used the Cannabis plant to treat a plethora of ailments. Practitioners in ancient China targeted malaria, menstrual symptoms, gout, and constipation. During medieval times, cannabis was used for pain, epilepsy, nausea, and vomiting, and in Western medicine it was commonly used as an analgesic.4,5 In the US, physicians prescribed Cannabis sativa for a multitude of illnesses until restrictions were put in place in the 1930s and then finally stopped using it in 1970 when the federal government listed marijuana as a Schedule I substance, claiming it an illegal substance with no medical value. California was the first state to go against the federal ban and legalize medical marijuana in 1996.6 As of June 2018, 9 states and Washington, DC, have legalized recreational marijuana, and 30 states and Washington, DC, allow for use of medical marijuana.7 The purpose of the present study is to describe the effects of CBD on anxiety and sleep among patients in a clinic presenting with anxiety or sleep as a primary concern.
CBD has demonstrated preliminary efficacy for a range of physical and mental health care problems. In the decade before 2012, there were only 9 published studies on the use of cannabinoids for medicinal treatment of pain; since then, 30 articles have been published on this topic, according to a PubMed search conducted in December 2017. Most notable was a study conducted at the University of California, San Diego’s Center for Medicinal Cannabis Research that showed cannabis cigarettes reduced pain by 34% to 40% compared with placebo (17% to 20% decrease in pain).8 In particular, CBD appears to hold benefits for a wide range of neurologic disorders, including decreasing major seizures. A recent large, well-controlled study of pediatric epilepsy documented a beneficial effect of CBD in reducing seizure frequency by more than 50%.9 In addition to endorphin release, the “runner’s high” experience after exercise has been shown to be induced in part by anandamide acting on CB1 receptors, eliciting anxiolytic effects on the body.10 The activity of CBD at 5-HT1A receptors may drive its neuroprotective, antidepressive, and anxiolytic benefits, although the mechanism of action by which CBD decreases anxiety is still unclear.11 CBD was shown to be helpful for decreasing anxiety through a simulated public speaking test at doses of 300 mg to 600 mg in single-dose studies.12–14 Other studies suggest lower doses of 10 mg/kg having a more anxiolytic effect than higher doses of 100 mg/kg in rats.15 A crossover study comparing CBD with nitrazepam found that high-dose CBD at 160 mg increased the duration of sleep.16 Another crossover study showed that plasma cortisol levels decreased more significantly when given oral CBD, 300 to 600 mg, but these patients experienced a sedative effect.17 The higher doses of CBD that studies suggest are therapeutic for anxiety, insomnia, and epilepsy may also increase mental sedation.16 Administration of CBD via different routes and long-term use of 10 mg/d to 400 mg/d did not create a toxic effect on patients. Doses up to 1500 mg/d have been well tolerated in the literature.18 Most of the research done has been in animal models and has shown potential benefit, but clinical data from randomized controlled experiments remain limited.
Finally, the most notable benefit of cannabis as a form of treatment is safety. There have been no reports of lethal overdose with either of the cannabinoids and, outside of concerns over abuse, major complications are very limited.19 Current research indicates that cannabis has a low overall risk with short-term use, but more research is needed to clarify possible long-term risks and harms.
Given the promising biochemical, physiologic, and preclinical data on CBD, a remarkable lack of randomized clinical trials and other formal clinical studies exist in the psychiatric arena. The present study describes a series of patients using CBD for treatment of anxiety or sleep disturbances in a clinical practice setting. Given the paucity of data in this area, clinical observations can be quite useful to advance the knowledge base and to offer questions for further investigation. This study aimed to determine whether CBD is helpful for improving sleep and/or anxiety in a clinical population. Given the novel nature of this treatment, our study also focused on tolerability and safety concerns. As a part of the evolving legal status of cannabis, our investigation also looked at patient acceptance.
Design and Procedures
A retrospective chart review was conducted of adult psychiatric patients treated with CBD for anxiety or sleep as an adjunct to treatment as usual at a large psychiatric outpatient clinic. Any current psychiatric patient with a diagnosis by a mental health professional (psychiatrist, psychiatric nurse practitioner, or physician assistant) of a sleep or anxiety disorder was considered. Diagnosis was made by clinical evaluation followed by baseline psychologic measures. These measures were repeated monthly. Comorbid psychiatric illnesses were not a basis for exclusion. Accordingly, other psychiatric medications were administered as per routine patient care. Selection for the case series was contingent on informed consent to be treated with CBD for 1 of these 2 disorders and at least 1 month of active treatment with CBD. Patients treated with CBD were provided with psychiatric care and medications as usual. Most patients continued to receive their psychiatric medications. The patient population mirrored the clinic population at large with the exception that it was younger.
Nearly all patients were given CBD 25 mg/d in capsule form. If anxiety complaints predominated, the dosing was every morning, after breakfast. If sleep complaints predominated, the dosing was every evening, after dinner. A handful of patients were given CBD 50 mg/d or 75 mg/d. One patient with a trauma history and schizoaffective disorder received a CBD dosage that was gradually increased to 175 mg/d.
Often CBD was employed as a method to avoid or to reduce psychiatric medications. The CBD selection and dosing reflected the individual practitioner’s clinical preference. Informed consent was obtained for each patient who was treated and considered for this study. Monthly visits included clinical evaluation and documentation of patients’ anxiety and sleep status using validated measures. CBD was added to care, dropped from care, or refused as per individual patient and practitioner preference. The Western Institutional Review Board, Puyallup, WA, approved this retrospective chart review.
Setting and Sample
Wholeness Center is a large mental health clinic in Fort Collins, CO, that focuses on integrative medicine and psychiatry. Practitioners from a range of disciplines (psychiatry, naturopathy, acupuncture, neurofeedback, yoga, etc) work together in a collaborative and cross-disciplinary environment. CBD had been widely incorporated into clinical care at Wholeness Center a few years before this study, on the basis of existing research and patient experience.
The sampling frame consisted of 103 adult patients who were consecutively treated with CBD at our psychiatric outpatient clinic. Eighty-two (79.6%) of the 103 adult patients had a documented anxiety or sleep disorder diagnosis. Patients with sole or primary diagnoses of schizophrenia, posttraumatic stress disorder, and agitated depression were excluded. Ten patients were further excluded because they had only 1 documented visit, with no follow-up assessment. The final sample consisted of 72 adult patients presenting with primary concerns of anxiety (65.3%; n = 47) or poor sleep (34.7%; n = 25) and who had at least 1 follow-up visit after CBD was prescribed.
Main Outcome Measures
Sleep and anxiety were the targets of this descriptive report. Sleep concerns were tracked at monthly visits using the Pittsburg Sleep Quality Index. Anxiety levels were monitored at monthly visits using the Hamilton Anxiety Rating Scale. Both scales are nonproprietary. The Hamilton Anxiety Rating Scale is a widely used and validated anxiety measure with 14 individual questions. It was first used in 1959 and covers a wide range of anxiety-related concerns. The score ranges from 0 to 56. A score under 17 indicates mild anxiety, and a score above 25 indicates severe anxiety. The Pittsburg Sleep Quality Index is a self-report measure that assesses the quality of sleep during a 1-month period. It consists of 19 items that have been found to be reliable and valid in the assessment of a range of sleep-related problems. Each item is rated 0 to 3 and yields a total score from 0 to 21. A higher number indicates more sleep-related concerns. A score of 5 or greater indicates a “poor sleeper.”
Side effects and tolerability of CBD treatment were assessed through spontaneous patient self-reports and were documented in case records. Any other spontaneous comments or complaints of patients were also documented in case records and included in this analysis.
Deidentified patient data were evaluated using descriptive statistics and plotted graphically for visual analysis and interpretation of trends.
The average age for patients with anxiety was 34 years (range = 18–70 years) and age 36.5 years for patients with sleep disorders (range = 18–72 years). Most patients with an anxiety diagnosis were men (59.6%, 28/47), whereas more sleep-disordered patients were women (64.0%, 16/25). All 72 patients completed sleep and anxiety assessments at the onset of CBD treatment and at the first monthly follow-up. By the second monthly follow-up, 41 patients (56.9%) remained on CBD treatment and completed assessments; 27 patients (37.5%) remained on CBD treatment at the third monthly assessment.
Table 1 provides means and standard deviations for sleep and anxiety scores at baseline and during the follow-up period for adults taking CBD. Figure 1 graphically displays the trend in anxiety and sleep scores over the study period. On average, anxiety and sleep improved for most patients, and these improvements were sustained over time. At the first monthly assessment after the start of CBD treatment, 79.2% (57/72) and 66.7% (48/72) of all patients experienced an improvement in anxiety and sleep, respectively; 15.3% (11/72) and 25.0% (18/72) experienced worsening symptoms in anxiety and sleep, respectively. Two months after the start of CBD treatment, 78.1% (32/41) and 56.1% (23/41) of patients reported improvement in anxiety and sleep, respectively, compared with the prior monthly visit; again, 19.5% (8/41) and 26.8% (11/41), respectively, reported worsening problems as compared with the prior month.