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Table 4 Literature details

From: Physicians’ experiences, attitudes, and beliefs towards medical cannabis: a systematic literature review

Reference Country Objective Study population and methods Results/conclusion Comments
Philpot 2019 [15] USA (Minnesota) To explore the attitudes, beliefs, and knowledge of healthcare providers in order to identify ongoing barriers, biases and knowledge gaps relating to medical cannabis. 62 providers answered a questionnaire (response rate: 31%). 76% of respondents were physicians. Experiences: 27.4% was registered to certify patients for medical cannabis, but one half reported having patients who had been certified for medical cannabis. 10% of providers had been certifying patients, and the mean number of patients certified was 4.
Attitudes and beliefs: 58.1% of the providers believed that medical cannabis was a legitimate medical therapy, and 38.7% believed that providers should be offering it to patients for managing medical conditions. 50% of providers were not ready to or did not want to answer patient questions about medical cannabis, and 77.4% of providers were interested in learning more about it. A majority (>  50%) of providers believed that medical cannabis was helpful for treating the qualifying medical conditions of cancer, terminal illness, and intractable pain. A majority of providers did not know if medical cannabis was effective for managing nearly one-half of the other state designated qualifying medical conditions. Few believed that medical cannabis improved quality of life domains. 38,7% of providers believed that medical cannabis interacted with medical therapies.
Minnesota has created a medical cannabis comprehensive program, and enrolled patients has access to extracted cannabis products in liquid or oil form.
Braun 2018 [16] USA To explore medical oncologists’ attitudes and knowledge in relation to prescription of medical cannabis and to explore its comparative effectiveness and risks. 237 medical oncologists answered a questionnaire (response rate: 63%).
The study explored whether oncologists reported discussing medical marijuana with patients, recommended it clinically and felt sufficiently informed to make such recommendations. The study also explored medical marijuana’s comparative effectiveness for several conditions and its risks compared with prescription of opioids.
Experiences: 80% conducted discussions about MM with patients or their families, and 46% recommended MM clinically.
Attitudes and beliefs:
30% of oncologists felt sufficiently informed to make recommendations regarding MM. More than half of oncologists who reported recommending MM did not consider themselves to have sufficient knowledge to make a recommendation. 67% viewed it as a helpful adjunct to standard pain management strategies, and 65% thought MM is equally or more effective than standard treatments for anorexia and cachexia.
It was legal for physicians to prescribe medical cannabis in 30 states and the District of Columbia.
Luba 2018 [17] USA (46 states) To examine palliative and hospice care providers’ attitudes and beliefs regarding the use of cannabis for terminally ill populations. 426 palliative and hospice care providers, (345 medical doctors, 58 nurses, and 23 others) answered a questionnaire (response rate was not reported). Attitudes and beliefs: 70% of all participants reported that cannabis could aid in end-of-life care. When examining individual symptoms, almost 90% believed that cannabis could be helpful in treating nausea, appetite loss and pain, almost 70% believed it could be helpful in the treatment of sleep problems, almost 60% in the treatment of irritability and emotional suffering. More than half of the study participants believed that adverse effects of cannabis would be equally or less problematic than conventional treatments when considering pain, appetite loss, nausea, sleep, and end-of-life care. 61% of all participants would recommend cannabis to patients with a terminal illness. More than half would recommend it for the treatment of appetite loss, nausea and pain. Respondents were from 46 different states. 45.3% of respondents were from states where cannabis was illegal, 36.2% were from states where cannabis was legal for medical use, and 22.1% were from states where cannabis was legal for recreational use. No further details on the prescription procedure or law on medical cannabis in each state were described.
Robinson 2018 [18] USA To explore the extent of dermatologists’ familiarity with and interest in cannabinoids as therapeutics. 531 dermatologists answered a questionnaire (response rate: 21.3%). Experiences: 55% reported at least one patient-initiated discussion about cannabinoids in the last year.
Attitudes and beliefs: 86% thought cannabinoids should be legal for medical treatment. Around 94% believed research into dermatologic uses of cannabinoids is worthwhile. 86% were willing to prescribe an approved cannabinoid as a topical treatment, and 71% were willing to prescribe an oral form. 64% did not know that cannabidiol is not psychoactive, and 29% did not know that tetrahydrocannabinol is psychoactive.
See the chapter “Procedures and definitions of medical cannabis prescriptions in included studies”.
Sideris 2018 [19] USA (New York) To probe physicians’ knowledge and perspectives of the New York State Medical Marijuana Programme (NY-MMP) and cannabinoids in patient care. 164 physicians with various specialties answered a questionnaire (response rate was not reported). 13% of the physicians were registered with the MMP, which authorized them to recommend medial cannabis. Experiences: 95% of registered physicians and 49% of nonregistered physicians had patients who inquired about medical cannabis within the past year. More than 75% reported having patients who used cannabis for symptom control. 25% of all respondents had recommended synthetic cannabinoid drugs, which were approved by the Food and Drug Administration, for patients.
Attitudes and beliefs: 71% believed that medical cannabis should be an option available to patients. 55% reported a willingness to discuss medical cannabis with patients if they felt their patients could benefit.
Medical cannabis was legal in the state of New York; Physicians can certify that patients have a qualifying condition and may recommend medical cannabis but cannot issue a prescription. To recommend medical cannabis, physicians must be registered with the NY-MMP, including a 4-h course which provides an overview of adverse effects, guidelines for dosing and administration etc.
Bega 2017 [20] USA (14 states) To gather data on cannabis-related prescribing practices and views regarding potential risks and benefits of medical cannabis among neurologists caring for patients with Parkinson’s disease. 56 neurologists answered a questionnaire (response rate: 63%). Experiences: 80% of all respondents reported having patients using medical cannabis (not described if they used it legally or illegally), and 95% had been requested to prescribe it. 10% of all respondents had recommended the use of cannabis to their patients. 23% reported having formal education on medical cannabis (not defined).
Attitudes and beliefs: 93% expected medical cannabis to be effective for appetite loss, 85% for pain, 80% for nausea, and 67% for anxiety. More than half expected that medical cannabis would worsen motivation, sleepiness, balance, forgetfulness, and hallucinations.
Medical cannabis was legal in eight of the surveyed states and illegal in six of the states. No further details of the law on medical cannabis were described.
Mathern 2015 [21] USA (study population was primarily from North America and Europe) To study opinions about the use of medical cannabis for people with epilepsy among physicians, other health professionals and patients/the public. (Only results from physicians are included in this review). 609 (140 epileptologists, 31 general neurologists, 9 general physicians, 36 basic researchers, 40 nurses and 353 patients/public) from different countries answered a questionnaire (response rate not reported as participants were not invited individually). Only results on health professionals are presented in this review.
The study compared epileptologists/neurologists and other physicians.
Attitudes and beliefs: Fewer epileptologists/neurologists supported the use of medical cannabis in the treatment of people with epilepsy compared with general medical personal. Law on medical cannabis was not described. See the chapter “Procedures and definitions of medical cannabis prescriptions in included studies”.
Kondrad 2013 [22] USA (Colorado) To study physicians’ attitudes towards medical cannabis. 520 general practitioners (GPs) answered a questionnaire (response rate of 30%).
The study compared physicians with and without experiences of prescribing medical cannabis to patients.
Experiences: 31% had ever recommended medical cannabis, primary to treat pain, muscle spasms and nausea. GPs reported a need for continuing medical education about medical cannabis.
Attitudes and beliefs: Those who had recommended medical cannabis were significantly more likely to be convinced of its benefits and less concerned about its risks than physicians who had never recommended it (72% vs. 26% respectively (p < 0.001)).
In Colorado, physicians could certify a patient registry card allowing patients to use cannabis for medical conditions.
Charuvastra 2005 [23] USA To investigate physicians’ practices and attitudes regarding the use of medical cannabis. 960 physicians (various specialities; addiction medicine/psychiatry, family practice, general psychiatry, internal medicine, obstetrics and gynaecology) answered a questionnaire (response rate: 66%).
The study compared physicians specialized in addiction medicine with other specialties.
Attitudes and beliefs: 36% reported that physicians should be able to prescribe medical cannabis legally. Compared to physicians specialized in addiction medicine (referent), internists and obstetrician/gynaecologists were significantly more likely to support medical use of cannabis, OR: 1.62 (1.01–2.50) and OR: 2.21 (1.39–3.53 respectively). Law on medical cannabis was not described. See the chapter “Procedures and definitions of medical cannabis prescriptions in included studies”.
Jacobs 2018 Australia To assess Australian psychiatrists’ and psychiatry trainees’ knowledge about and attitudes towards medicinal cannabinoids, given the recent relaxation of cannabinoid-prescribing laws in Australia. 88 physicians responded to an online accessible survey, with 55 completing all items, 23 psychiatrists and 32 trainees (response rate: 1.1%). Attitudes and beliefs: 54% of respondents would prescribe medical cannabinoids if it was legal for them to do so (trainees did not have the authority). Participants believed there was evidence for the use of cannabidiol and tetrahydrocannabinol in treating childhood epilepsy, chronic pain, and nausea and vomiting. Generally, they were poor at differentiating between indications for cannabidiol versus tetrahydrocannabinol. They were most concerned about medicinal cannabinoids leading to psychotic symptoms, addiction and dependence, apathy and recreational use. In Australia there was legal access to medical cannabis for patients approved for it by a physician.
Karanges 2018 [24] Australia To examine the knowledge and attitudes of Australian GPs towards medical cannabis, including patient demands, GP perceptions of therapeutic effects and potential harms, perceived knowledge and willingness to prescribe. 640 GPs answered a questionnaire (response rate 37%).
Distribution of printed questionnaires at one-day general practice educational seminars held in five major Australian Cities.
Experience: (61.5%) reported one or more patient enquiries about medical cannabis in the last 3 months.
Attitudes and beliefs:
Most felt that their own knowledge was inadequate and only 28.8% felt comfortable discussing medical cannabis with patients. Over half (56.5%) supported availability on prescription, with the preferred access model involving trained GPs prescribing independently of specialists. Support for use of medical cannabis was condition-specific, with strong support for use in cancer pain, palliative care and epilepsy, and much lower support for use in depression and anxiety.
In Australia there was legal access to medical cannabis for patients approved for it by a physician.
Irvine 2006 [25] Australia To examine GPs’ attitudes to and knowledge of medical cannabis. 32 GPs answered a questionnaire (response rate not reported). Attitudes and beliefs: 75% of the sample would be prepared to prescribe medical cannabis if it was legal, supported by peers and based on good-quality clinical research evidence. In Australia, medical cannabis was illegal at the time.
St-Amant 2015 [26] Canada (Quebec) To measure prevalence and identified determinants of cannabinoid prescriptions for the management of chronic noncancer pain among physicians. 166 physicians (family physicians/GPs and other specialties) answered a questionnaire (response rate of 52.2%). Experiences: 27% had prescribed cannabinoids for all potential indications in the previous year. 23% had prescribed it for chronic noncancer pain, and of these 18% were medical cannabis. The majority had prescribed it to less than five patients. Physicians were not comfortable prescribing cannabinoids, with about 80% reporting a degree of comfort below 6 on a 1–10-point scale. Physicians reported medical education and having guidelines and more clinical data as factors which could increase their comfort level. Low level of comfort with prescribing medical cannabis for chronic noncancer pain was associated with low prevalence of prescription (OR: 1.25, CI: 1,01-1,55). See the chapter “Procedures and definitions of medical cannabis prescriptions in included studies”.
Ziemianski 2015 [27] Canada To determine physicians’ educational needs regarding medical cannabis. 426 physicians (44% GPs/family physicians and 51% other specialists, 4% other) answered a questionnaire (response rate: 1%, calculated from reported numbers). Experiences: 79% had been approached by a patient to discuss the use of medical cannabis, and 39% had initiated a discussion with the patient about it. 59% had ever prescribed medical cannabis. There was a gap between current and desired knowledge concerning dosing, development and treatment plans, and the physicians reported a need for better knowledge of risks and benefits.
Attitudes and beliefs: 65% were concerned that patients who requested medical cannabis actually wanted it for recreational purposes. The majority of physicians reported that no other health professionals than physicians should be authorised to approve medical cannabis.
See the chapter “Procedures and definitions of medical cannabis prescriptions in included studies”.
Fitzcharles 2014 [28] Canada To examine confidence in the knowledge of cannabinoids among rheumatologists. 128 rheumatologists answered a questionnaire (response rate: 25%).
The study compared responders who are confident and not confident in knowledge of cannabinoids.
Experiences: 13% had ever recommended medical cannabis, and 90% were not confident in writing a prescription when required to indicate dosing, frequency, and method of administration. The study found that 7% of the not-confident vs. 27% of the confident rheumatologists had previously recommended a trial of medical cannabis (p = 0.006).
Attitudes and beliefs: 25% believed there was a role for medical cannabis in the management of rheumatic diseases. Barriers which would prevent physicians from prescribing medical cannabis were history/potential of drug abuse/addiction, mental health and lack of clear diagnosis/non-severity of pain complaints. 42% of the confident physicians would prescribe medical cannabis if all conventional treatments had failed, which only 23% of the non-confident physicians would.
See the chapter “Procedures and definitions of medical cannabis prescriptions in included studies”.
Crowley 2017 [29] Ireland To assess levels of support for use of medical cannabis among GPs. 565 GPs answered a questionnaire (response rate 15%).
The study compares GPs with and without special training in addiction treatment.
Attitudes and beliefs: Almost 60% supported legislation of cannabis for medical use. GPs with training in addiction treatment were significantly less supportive that cannabis should be legalised for medical use compares to GPs with no training (65.1% vs. 78.5% respectively (p = 0.003)).
GPs with training in addiction treatment were significantly less supportive that medical cannabis has a role in pain management (80.1% vs. 88.2%, p = 0.03), treatment of multiple sclerosis (85.5 vs. 92.4%, p = 0.04), and palliative care (83.3% vs. 90.0%, p = 0.05), compared to GPs with no training.
See the chapter “Procedures and definitions of medical cannabis prescriptions in included studies”.
Van Hout 2017 [30] Ireland To study levels of support for medical cannabis among GPs. 565 GPs answered a qualitative survey with open-ended questions (response rate: 15%). Attitudes and beliefs: The identified attitudes were mixed and centred on the evidence base and quality control. Some physicians were convinced about effects but concerned about the lack of evidence and patient misuse. See the chapter “Procedures and definitions of medical cannabis prescriptions in included studies”.
Sharon 2018 [31] Israel To examine the attitudes, beliefs, and personal experience of pain specialists (physicians) in Israel regarding the medical use of cannabis. 50 registered, active, board-certified pain specialists answered a web-based questionnaire (response rate: 64%). Experiences: 64% of all practicing pain specialists in Israel responded. 95% of them prescribed medical cannabis. Among them, 63% found cannabis moderately to highly effective, 56% have encountered mild or no side effects, and only 5% perceived it as significantly harmful. Common indications were neuropathic pain (65%), oncological pain (50%), arthralgias (25%), and any intractable pain (29%). Leading contraindications were schizophrenia (76%), pregnancy/breastfeeding (65%), and age < 18 years (59%).
Attitudes and beliefs: Only 12% rated medical cannabis as more hazardous than opiates. 54% would like to see cannabis legalized in Israel. The majority (80%) reported they were inadequately trained to prescribe medical cannabis.
See the chapter “Procedures and definitions of medical cannabis prescriptions in included studies”.
Zolotov 2018 [9] Israel To study physicians’ views of medical cannabis and its possible integration into clinical practice. Qualitative interviews with 24 physicians (specialists or physicians currently specializing in oncology, pain medicine, and family medicine) were conducted. Attitudes and beliefs: The study identified two major narratives:
1) Cannabis as non-medicine: Conventional medicine was seen as the ideal option and physicians pointed out that medical cannabis failed to comply with the standards of biomedicine. Physicians pointed out the lack of scientific evidence of safety and efficacy. They presented medical cannabis as a social and criminal matter, which should not fall under the professional domain of medicine.
2) Cannabis as medicine: Hands-on experience was mentioned as having a crucial impact on attitudes and practices. Physicians pointed out the limitations of evidence-based medicine and argued that other aspects of health care are unsupported by evidence. When considering very sick people, physicians gave much less weight to the lack of evidence and potential harms. Besides, cannabis was described as medicine for patients with an uncontested diagnosis which can be proved by objective laboratory procedures.
See the chapter “Procedures and definitions of medical cannabis prescriptions in included studies”.
Ablin 2016 [32] Israel To survey rheumatologists’ attitudes towards the use of medical cannabis. 23 rheumatologists answered a questionnaire (response rate of 19.3%). Experiences: 48% had previously prescribed medical cannabis, and 78% were not confident in writing prescriptions when required to indicate dosing, frequency and method of administration.
Attitudes and beliefs: 83% were willing to prescribe medical cannabis if conventional treatments failed, and 9% would prescribe it regardless of previous treatments.
See the chapter “Procedures and definitions of medical cannabis prescriptions in included studies”.
Ebert 2015 [33] Israel To examine physicians’ experiences, knowledge and attitudes towards medical cannabis. 27 physicians (various specialities: oncology, pain medicine, rehabilitation, psychiatry and neurology) answered a questionnaire (response rate of 72%).
The study compared physicians who had ever recommended medical cannabis with those who had not.
Experiences: About 90% have been exposed to a patient using medical cannabis, and 60% had recommended it to at least one patient. Compared to physicians who had never recommended medical cannabis (40.3%), physicians who had recommended it once or more (59.7) reported themselves as having a significantly greater knowledge of dosage, ways of administration and risk and adverse effects (p < 0.05).
Clinical experiences and knowledge from medical literature and other physicians were influencing physicians’ decision on recommendation of medical cannabis.
Attitudes and beliefs: About 80% reported that medical cannabis could be helpful for chronically and terminally ill patients. About 60% reported that physicians should not be permitted to prescribe it to patients directly, without the Ministry of Health’s licensing procedure. 88% reported a need for more education on medical cannabis.
See the chapter “Procedures and definitions of medical cannabis prescriptions in included studies”.