Respondents
Of the 1804 respondents who commenced the survey, 184 did not meet eligibility criteria, and 192 did not give consent. Data were excluded for 70 respondents who provided no further information beyond demographics questions, 3 respondents who indicated that none of their cannabis use was for medical purposes, and 7 who provided implausible responses to numerous questions. Of the remaining 1388 respondents, 909 (65%) completed the entire survey.
Most respondents became aware of the survey via social media: 336/1387 (24.2%) through facebook, and 838/1387 (59.5%) through other social media (e.g. Instagram, Twitter, Snapchat, Reddit, Whirlpool, Bluelight). Others were recruited through friends (4.7%, 65/1387), medical cannabis providers (1.8%, 25/1387), the website for the Lambert Initiative of Cannabinoid Therapeutics, a philanthropically-funded research centre at the University of Sydney (1.7%, 23/1387), consumer groups (0.9%, 13/1387), traditional media (TV, radio, newspaper) (0.8%, 11/1387), doctors/healthcare providers (1.0%, 8/1387), cannabis access clinics (0.4%, 6/1387), and ‘other’ sources (4.5%, 62/1387). The proportion of respondents recruited through facebook in CAMS-18 was much lower than in CAMS-16, and the proportion through other social media much higher (V=0.65).
Respondent characteristics
Respondents’ characteristics are reported in Table 1. Respondents’ mean (± Standard Deviation) age was 43.4±13.9 years and the majority were male (57.6%, 799/1387). Most respondents were employed (59.2%, 821/1387) and had attained either a trade/vocational certificate or a university degree (78.7%, 1092/1387). Compared to the CAMS-16 cohort the CAMS-18 cohort were older and had proportionally greater numbers who (i) were female, (ii) were in a relationship, and (iii) had a tertiary qualification; however, these demographic differences were small (g<0.50 or V<0.30) except for education level where there was a medium-sized effect (V=0.30).
Cannabis use
Lifetime cannabis use history indicated that 19.1% (212/1109) had never used cannabis prior to using it for medical reasons, 35.7% (396/1109) reported previous non-medical cannabis use but had quit for 12 months or more prior to initiating medical cannabis use, and 45.2% (501/1109) were using cannabis non-medically at the time they began using it medically. The proportion of respondents who had never used cannabis prior to using it for medical reasons was similar in both CAMS-16 and CAMS-18 (V=0.07).
Table 1: Demographic characteristics of the CAMS-18 sample (n=1387)
Characteristic
|
|
Age, mean (SD)
|
43.4 (13.9)
|
Gender
Female
Male
Other
|
560 (40.4%)
799 (57.6%)
28 (2.0%)
|
Relationship Status
Partnered (currently in relationship, including defacto and married)
Single (not currently in a relationship, including separated, divorced, widowed)
|
861 (62.1%)
526 (37.9%)
|
Indigenous Status
Aboriginal and/or Torres Strait Islander
Not Aboriginal and/or Torres Strait Islander
|
56 (4.0%)
1331 (96.0%)
|
Highest Education Level Attained
Primary School
Secondary School
Trade or Vocational College
University Degree
Other
|
14 (1.0%)
278 (20.0%)
461 (33.2%)
631 (45.5%)
3 (0.2%)
|
Employment Status
Full-time work
Part-time work
Home duties
Student
Unemployed
Retired
|
633 (45.6%)
188 (13.6%)
78 (5.6%)
77 (5.6%)
63 (4.5%)
128 (9.2%)
|
Note: Missing values excluded from denominator when calculating percentages.
The mean estimated proportion of cannabis use for medical purposes (as a proportion of total use) was 83.2±20.6% (Table 2). Respondents reported using medical cannabis on a median of 18 days in the past 28 days (IQR=4, 28; mean=15.8±11.2).
Table 2: Patterns of cannabis use
Characteristic
|
n
|
|
Age first tried cannabis for any reason, Mean (SD)
|
1110
|
20.5 (11.6)
|
Age first regular cannabis use any reason, Mean (SD)
|
1110
|
25.8 (16.3)
|
Age first regular cannabis use for medical reason, Mean (SD)
|
1110
|
32.6 (17.5)
|
Never used cannabis regularly for any reason, N (%)
|
1110
|
134 (12.1%)
|
Number of days in previous 28 used cannabis for any reason
Mean (SD)
Median (IQR)
|
1110
|
17.3 (10.9)
20 (5-28)
|
Number of days in previous 28 used cannabis for medical reasons
Mean (SD)
Median (IQR)
|
1110
|
15.8 (11.2)
18 (4-28)
|
Estimated proportion of cannabis use for medical reasons, mean (SD)
|
1095
|
83.2% (20.6%)
|
Usual number of times using cannabis per day for any reason
Mean (SD)
Median (IQR)
|
1110
|
3.3 (3.7)
2 (1-4)
|
Weekly cost of medical cannabis, Mean (SD)
|
1101
|
$60.68 ($94.20)
|
Weekly cost of medical cannabis with respondents who did not pay excluded, Mean (SD)
|
812
|
$82.27 ($101.27)
|
Median (IQR) reported for count variables only. IQR = Interquartile range
Most respondents consumed their cannabis via an inhaled (71.4%; 788/1104) route (compared with oral [26.5%, 293/1104] or other [2.1%, 23/1104] routes); however, there was a stronger preference for oral or vaporised routes of administration over traditional smoked routes such as joints, pipes, or bongs (Figure 1). Compared to CAMS-16, a lower proportion of respondents in CAMS-18 indicated that they consumed and would prefer to consume their medical cannabis by inhalation, and a greater proportion indicated they consumed and would prefer to consume their medical cannabis orally; however this effect was small (V=0.15).
Figure 1: Usual and preferred methods of administering medical cannabis
Compared to the CAMS-16 cohort, CAMS-18 respondents tended to: (i) have started using cannabis later and used less cannabis for either medical or other reasons, and (ii) use a greater percentage of cannabis for medical purposes compared to non-medical purposes; however, these differences were all small to negligible (all g<0.50).
Composition of medical cannabis
Respondents reported they either did not know the composition of their cannabis (25.8%, 284/1103) or that it varied significantly between batches (23.9%, 264/1103). 16.4% (181/1103) reported their medical cannabis contained approximately equal levels of THC and CBD, 21.3% (235/1103) reported it contained predominately THC (with either no, or small amounts of other cannabinoids), 12.2% (135/1103) reported it contained predominately CBD, and 0.4% (4/1103) reported ‘other’. Most (63.4%, 699/1105) were concerned about the possibility of contaminants (e.g. heavy metals, pesticides) in their cannabis.
Conditions treated with medical cannabis
Respondents were asked to select from a structured list, up to five health conditions (“Any condition” column, Table 3), and the main condition that they had treated using medical cannabis. The categories most commonly endorsed for “Any condition” were insomnia (41.5%, 573/1382), back pain (34.5%, 477/1382), anxiety (32.6%, 450/1382), and depression. (27.9%, 386/1382). The most frequent main conditions were anxiety (12.6%, 168/1331), back pain (10.1%, 135/1331), depression (8.5%, 113/1331) and insomnia (7.1%, 94/1331).
Table 3: Conditions reported as reasons for using medical cannabis.
Condition
|
Rank
|
Main Conditiona (n = 1331)
|
Any Conditionb (n = 1382)
|
Condition
|
n (%)c
|
Condition
|
n (%)c
|
Pain
|
1
2
3
4
5
|
Total
Back pain
Arthritis
Nerve pain
Fibromyalgia
All others
|
499 (37.5%)
135 (10.1%)
79 (5.9%)
75 (5.6%)
52 (3.9%)
158 (12.0%)
|
Total
Back pain
Arthritis
Headaches
Neck pain
All others
|
852 (61.6%)
477 (34.5%)
262 (19.0%)
215 (15.6%)
202 (14.6%)
638 (46.1%)
|
Mental Health
|
1
2
3
4
5
|
Total
Anxiety
Depression
PTSD
Bipolar affective disorder
All others
|
437 (32.8%)
168 (12.6%)
113 (8.5%)
82 (6.2%)
15 (1.1%)
59 (4.5%)
|
Total
Anxiety
Depression
PTSD
Addiction to other substances
All others
|
621 (44.9%)
450 (32.6%)
386 (27.9%)
191 (13.8%)
67 (4.8%)
198 (14.3%)
|
Sleep
|
1
2
3
4
5
|
Total
Insomnia
Circadian rhythm disorder
Sleep movement disorder
Parasomnia
All others
|
123 (9.2%)
94 (7.1%)
9 (0.7%)
9 (0.7%)
1 (0.1%)
10 (0.8%)
|
Total
Insomnia
Sleep movement disorder
Circadian rhythm disorder
Sleep breathing disorder
All others
|
679 (49.1%)
573 (41.5%)
140 (10.1%)
74 (5.4%)
55 (4.0%)
70 (5.1%)
|
Neurological
|
1
2
3
4
5
|
Total
Epilepsy
Autism
Multiple Sclerosis
Dementia
All others
|
69 (5.2%)
26 (2.0%)
14 (1.1%)
13 (1.0%)
1 (0.1%)
15 (1.2%)
|
Total
Epilepsy
Autism
Multiple Sclerosis
Dementia
All others
|
147 (10.6%)
45 (3.3%)
27 (2.0%)
18 (1.3%)
6 (0.4%)
71 (5.2%)
|
Cancer
|
1
2
3
4
5
|
Total
Blood cancers
Gastrointestinal cancers
Brain
Breast
All others
|
50 (3.8%)
8 (0.6%)
6 (0.5%)
5 (0.4%)
5 (0.4%)
26 (2.1%)
|
Total
Breast
Skin
Brain
Reproductive
All others
|
106 (7.7%)
19 (1.4%)
17 (1.2%)
15 (1.1%)
15 (1.1%)
57 (4.1%)
|
Gastrointestinald
|
1
2
3
4
|
Total
Crohn’s disease
Ulcerative colitis
Irritable Bowel syndrome
All others
|
40 (3.0%)
10 (0.8%)
10 (0.8%)
9 (0.7%)
11 (0.8%)
|
Total
Irritable Bowel Syndrome
Ulcerative Collitis
Crohn’s Disease
All others
|
175 (12.7%)
101 (7.3%)
25 (1.8%)
19 (1.4%)
60 (4.3%)
|
Other
|
1
2
3
4
5
|
Total
Auto-immune condition
Gynaecological condition
Infectious disease
Skin condition
All others
|
113 (8.5%)
33 (2.5%)
25 (1.9%)
9 (0.7%)
9 (0.7%)
37 (2.9%)
|
Total
Auto-immune condition
Skin condition
Respiratory conditions
Gynaecological condition
All others
|
165 (11.9%)
64 (4.6%)
43 (3.1%)
41 (3.0%)
31 (2.2%)
88 (6.5%)
|
a: respondents could only select one main condition that they treated with cannabis; b: respondents could select up to five conditions that they treated with cannabis. c: percentages displayed represent the proportion each specific category makes up of the entire available sample (i.e. n/1331 for main condition and n/1382 for any condition). d: There were only three specific conditions listed under the Gastrointestinal group, and an ‘other’ category.
The proportions of respondents who reported Pain, Mental Health/Substance Use, Sleep, or other conditions as the main conditions they treated with MC were very similar across both CAMS-16 and CAMS-18 surveys (V=0.06).
Patient reports of symptoms being managed, effectiveness, side-effects, and other adverse consequences
The symptoms that respondents reported being most often managed with medical cannabis mirrored the main conditions being treated (above section): pain (48.0%, 666/1388), anxiety (44.0%, 611/1388), and sleep problems (31.3%, 434/1388). The overwhelming majority of respondents reported symptom improvement following medical cannabis use (Figure 2).
Figure 2: Most common symptoms treated with medical cannabis and change in those symptoms after treatment with medical cannabis
Side effects were commonly reported (Table 4), although relatively few reported these to be severe and/or intolerable. The most common mild and tolerable side effects were dry mouth (61.5%, 601/977), increased appetite (59.2%, 578/976), drowsiness (54.7%, 534/976), and eye irritation (30.2%, 294/974). The most common severe and/or intolerable side-effects were increased appetite (4.8%, 47/976), anxiety (2.4%, 23/974), dry mouth (2.4%, 23/977), and lack of energy or fatigue (2.1%, 20/973).
Table 4: Side-effect profile of medical cannabis use
|
Severity
|
Side-Effect
|
Mild and Tolerable
|
Severe and/or Intolerable
|
Dry Mouth (n=977)
|
601 (61.5%)
|
23 (2.4%)
|
|
Increased appetite (n=976)
|
578 (59.2%)
|
47 (4.8%)
|
|
Drowsy (n=976)
|
534 (54.7%)
|
13 (1.3%)
|
|
Eye Irritation (n=974)
|
294 (30.2%)
|
8 (0.8%)
|
|
Lack of Energy or Fatigue (n=973)
|
287 (29.5%)
|
20 (2.1%)
|
|
Anxiety (n=974)
|
228 (23.4%)
|
23 (2.4%)
|
|
Memory Impairment (n=973)
|
227 (23.3%)
|
16 (1.6%)
|
|
Dehydration (n=975)
|
220 (22.6%)
|
9 (0.9%)
|
|
Confusion (n=975)
|
144 (14.8%)
|
9 (0.9%)
|
|
Respiratory complaints (n=973)
|
141 (14.5%)
|
5 (0.5%)
|
|
Dizzy (n=974)
|
137 (14.1%)
|
6 (0.6%)
|
|
Residual bad taste in mouth (n=973)
|
135 (13.9%)
|
12 (1.2%)
|
|
Decreased Appetite (n=975)
|
127 (13.0%)
|
8 (0.8%)
|
|
Paranoia (n=973)
|
111 (11.4%)
|
9 (0.9%)
|
|
Racing heart or palpitations (n=972)
|
106 (10.9%)
|
11 (1.1%)
|
|
Sweating (n=974)
|
90 (9.2%)
|
10 (1.0%)
|
|
Depressed (n=974)
|
87 (8.9%)
|
15 (1.5%)
|
|
Headaches (n=973)
|
73 (7.5%)
|
11 (1.1%)
|
|
Sleep disturbance (n=973)
|
72 (7.4%)
|
14 (1.4%)
|
|
Diarrhea (n=974)
|
65 (6.7%)
|
7 (0.7%)
|
|
Constipation (n=974)
|
52 (5.3%)
|
7 (0.7%)
|
|
Nasal Complaints (n=973)
|
46 (4.7%)
|
8 (0.8%)
|
|
Gastro-Intestinal Irritation (n=973)
|
44 (4.5%)
|
7 (0.7%)
|
|
Allergy (n=974)
|
41 (4.2%)
|
5 (0.5%)
|
|
Panic Attacks (n=973)
|
38 (3.9%)
|
8 (0.8%)
|
|
Shaking/tremor (n=972)
|
37 (3.8%)
|
4 (0.4%)
|
|
Nausea/vomiting (n=973)
|
36 (3.7%)
|
6 (0.6%)
|
|
Delusion (n=974)
|
24 (2.5%)
|
4 (0.4%)
|
|
Hallucinations (n=973)
|
22 (2.3%)
|
3 (0.3%)
|
|
Cannabis hyperemesis (n=974)
|
12 (1.2%)
|
8 (0.8%)
|
|
Other (n=970)
|
3 (0.3%)
|
11 (1.1%)
|
|
Almost half the respondents (47.6%, 448/942) indicated that the cost of medical cannabis placed a significant strain on their finances, 79.7% (751/942) worried about being arrested or other legal problems, and 37.5% (353/942) were worried about employment issues. 9.3% of respondents (88/942) reported they had to undergo workplace drug testing.
Accessing medical cannabis
When asked to list their main source of supply, 46.2% of respondents (482/1044) indicated they obtained their medical cannabis from ‘recreational dealers’, 25.3% (264/1044) from friends or family, 11.6% (121/1044) by growing their own, 7.2% (75/1044) from illicit medicinal cannabis suppliers, 5.1% (53/1044) from online suppliers, and 4.7% (49/1044) from ‘other’ sources. Only 2.4% of respondents (25/1044) indicated they had accessed licit medical cannabis prescribed by a doctor. These proportions were very similar to the proportions observed in the CAMS-16 survey (V=0.14).
When asked why they had not accessed medical cannabis legally, 47.8% (433/906) of respondents indicated they did not know a medical practitioner willing to prescribe, 32.0% (290/906) were not aware they could access medical cannabis legally, 21.2% (192/906) indicated licit cannabis was too expensive, 18.4% (167/906) believed their medical practitioner was not interested or unwilling to prescribe cannabis, 12.7% (115/906) indicated they wanted their medical cannabis use to remain confidential from their healthcare providers, 9.5% (86/906) said they preferred illicit cannabis, and 11.6% (105/906) gave other reasons.
One quarter (26.2%, 289/1101) reported not paying for their cannabis, but indicated they were willing to pay a weekly mean (± SD) of AUD$38.33±63.92, (median AUD$25, IQR: $10, $50) for prescribed products. Those respondents who did pay for cannabis estimated spending AUD$82.27±101.27 per week (median $50, IQR: $20, $100; $12.24 less than respondents in CAMS-16, g=0.13), and indicated that they were willing to pay AUD$68.67±66.64 (median $50, IQR: $25, $100) for prescribed cannabis products.
Seeking information about medical cannabis
When asked about their decision to try medical cannabis, most (51.5%, 523/1015) indicated that they discovered the benefits on their own (using cannabis and noticed symptoms improved), 10.5% (107/1015) reported internet-based media (e.g. Facebook, Reddit), 9.9% (100/1015) by a friend or family member, 6.5% (66/1015) by a medical cannabis advocacy group, 5.6% (57/1015) by a disease-specific consumer group, 5.0% (51/1015) by a healthcare provider, and the remainder (10.9%, 111/1015) from other sources.
Although the initial interest in medical cannabis was generated by sources other than health professionals, most respondents (63.2%, 641/1015) had discussed their medical cannabis use with a healthcare provider, including their GP (83.6%, 536/641), medical specialist (54.3%, 348/641), psychologist (40.0%, 256/641), nurse (17.5%, 112/641), alternative medicine provider (17.2%, 110/641), and pharmacist (12.9%, 83/641).
Accessing medically prescribed medical cannabis products
The 25 respondents who had accessed prescribed medical cannabis products had been accessing it for an average of 4.8±3.8 months (median 3, IQR: 2, 6), prescribed by a medical specialist (64%; 16) or GP (36%, 9) for indications including fibromyalgia, multiple sclerosis, neuropathy, epilepsy, autism, Alzheimer’s, mesothelioma, post-traumatic stress disorder, and back pain. Respondents estimated 18±22.5 weeks (median 12, IQR: 4, 25) between their first cannabis-specific consultation with their doctor and receiving their first dose of medical cannabis. Although the numbers were too small to draw any firm conclusions, feedback from the 25 respondents who had accessed medical cannabis legally indicated generally positive ratings of their experience of product consistency (17 [68%] preferred licit supplies, 6 [24%] preferred illicit supplies, 2 [8%] no preference); ease of access (15 [60%] preferred licit to 7 [28%] illicit), cost (11 [44%] preferred licit to 8 [32%] illicit), effectiveness (11 [44%] preferred licit to 6 [24%] illicit), fewer side effects (13 [52%] preferred licit to 5 [20%] illicit), and legal status (20 [80%] preferred licit to 2 [8%] illicit).
Attitudes to regulation of medical cannabis
Most respondents (78.3%, 721/921) indicated that people should be able to buy and use medical cannabis without approval by a medical practitioner, 92% (850) that medical cannabis should be part of routine healthcare in Australia, 70.7% (652) that the government should subsidise the cost of medical cannabis and 91.1% (839) that medical cannabis should meet safety standards (e.g. known strength, composition and contaminant-free). Most thought that the Australian regulatory framework for accessing medical cannabis did not work well (91.0%, 838/921), that the cost of licit medical cannabis was prohibitively expensive (62.6%, 577/921), and that the current model was difficult for patients to negotiate (87.3%, 804/921).