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Table 3 Summary of findings. GRADE Working Group grades of evidence. High quality: Further research is very unlikely to change our confidence in the estimate of effect. Moderate quality: Further research is likely to have an important impact on our confidence in the estimate of effect and may change the estimate. Low quality: Further research is very likely to have an important impact on our confidence in the estimate of effect and is likely to change the estimate. Very low quality: We are very uncertain about the estimate

From: Medical cannabinoids: a pharmacology-based systematic review and meta-analysis for all relevant medical indications

  Comparison No. of participants (studies) I2 (%) GRADE Relative effect (95% CI) Anticipated absolute effects
Outcome Risk with control Risk difference with Cannabinoids
Chronic pain Dronabinol vs Placebo 1395 (15 RCTs) 53
MODERATE c
   SMD 0.31 lower
(0.46 lower to 0.15 lower)
Dronabinol vs Active 14 (1 RCT)      SMD 0.73 higher
(0.1 lower to 1.56 higher)
Nabilone vs Placebo 363 (9 RCTs) 70
LOW c,g
   SMD 0.41 lower
(0.76 lower to 0.06 lower)
Nabilone vs Active 262 (3 RCTs) 83
VERY LOW c,e
   SMD 0.08 lower
(0.54 lower to 0.38 higher)
Cannabidiol vs Placebo 129 (1 RCT)      SMD 0.01 higher
(0.34 lower to 0.35 higher)
Nabiximols vs Placebo 3238 (21 RCTs) 65
MODERATE c
   SMD 0.23 lower
(0.34 lower to 0.12 lower)
Spasticity Dronabinol vs Placebo 704 (6 RCTs) 52
LOW c,f
   SMD 0.08 lower
(0.34 lower to 0.17 higher)
Nabilone vs Placebo 44 (2 RCTs) 68
VERY LOW a,c,g
   SMD 0.7 lower
(1.56 lower to 0.16 higher)
Nabiximols vs Placebo 1658 (14 RCTs) 68
MODERATE c
   SMD 0.36 lower
(0.54 lower to 0.19 lower)
Nausea/vomiting Dronabinol vs Placebo 495 (8 RCTs) 61
LOW c,f
   SMD 0 .21 lower
(0.49 lower to 0.07 higher)
Dronabinol vs Active 308 (5 RCTs) 0
LOW a,g
   SMD 0.28 lower
(0.47 lower to 0.1 lower)
Nabilone vs Placebo 603 (4 RCTs) 61
LOW c,f
   SMD 0.09 lower
(0.36 lower to 0.18 higher)
Nabilone vs Active 627 (11 RCTs) 46
LOW b,c
   SMD 0.44 lower
(0.62 lower to 0.26 lower)
Nabiximols vs Placebo 393 (6 RCTs) 56
VERY LOW a,e
   SMD 0.23 lower
(0.55 lower to 0.08 higher)
Appetite Dronabinol vs Placebo 599 (10 RCTs) 81
MODERATE c
   SMD 0.51 lower
(0.87 lower to 0.15 lower)
Dronabinol vs Active 795 (3 RCTs) 86
LOW c,f
   SMD 0.02 lower
(0.39 lower to 0.34 higher)
Nabilone vs Placebo 187 (4 RCTs) 74
VERY LOW c,e
   SMD 0.44 lower
(0.98 lower to 0.11 higher)
Nabilone vs Active 130 (3 RCTs) 85
VERY LOW a,d, g
   SMD 0.24 higher
(0.51 lower to 0.99 higher)
Cannabidiol vs Placebo 27 (1 RCT)      SMD 0.1 higher
(0.66 lower to 0.85 higher)
Nabiximols vs Placebo 430 (6 RCTs) 66
LOW c,f
   SMD 0.25 lower
(0.61 lower to 0.1 higher)
Amyotrophic lateral sclerosis Dronabinol vs Placebo 22 (1 RCT)      SMD 0.26 higher
(0.17 lower to 0.68 higher)
Nabiximols vs Placebo 59 (1 RCT)      SMD 0.38 higher
(0.13 lower to 0.90 higher)
Chorea Huntington Nabilone vs Placebo 74 (1 RCT)      SMD 0.45 lower
(0.79 lower to 0.11 lower)
Cannabidiol vs Placebo 30 (1 RCT)      SMD 0.18 higher
(0.33 lower to 0.69 higher)
Nabiximols vs Placebo 50 (1 RCT)      SMD 0.17 higher
(0.23 lower to 0.56 higher)
Dystonia Dronabinol vs Placebo 14 (1 RCT)      SMD 0.05 higher
(0.69 lower to 0.79 higher)
Nabilone vs Placebo 26 (1 RCT)      SMD 0.49 lower
(1.07 lower to 0.08 higher)
Nabiximols vs Placebo 50 (1 RCT)      SMD 0
(0.39 lower to 0.39 higher)
Epilepsy Cannabidiol vs Placebo 956 (6 RCTs) 0
HIGH
   SMD 0.5 lower
(0.62 lower to 0.38 lower)
Glaucoma Dronabinol vs Placebo 12 (1 RCT)      SMD 1.28 lower
(2.36 lower to 0.2 lower)
Nabiximols vs Placebo 12 (1 RCT)      SMD 0.82 higher
(0.1 lower to 1.75 higher)
IBS Dronabinol vs Placebo 81 (2 RCTs) 85
VERY LOW c,e
   SMD 0
(1.09 lower to 1.09 higher)
MS Dronabinol vs Placebo 660 (2 RCTs) 74
LOW c,f
   SMD 0.15 lower
(0.51 lower to 0.22 higher)
Nabiximols vs Placebo 863 (5 RCTs) 65
LOW c,f
   SMD 0.14 lower
(0.38 lower to 0.11 higher)
Parkinson Nabilone vs Placebo 51 (2 RCTs) 46
VERY LOW c,e
   SMD 0.38 lower
(1.05 lower to 0.29 higher)
Cannabidiol vs Placebo 101 (3 RCTs) 0
MODERATE g
   SMD 0.41 lower
(0.75 lower to 0.08 lower)
ADHD Nabiximols vs Placebo 30 (1 RCT)      SMD 0.83 lower
(1.58 lower to 0.09 lower)
Anorexia nervosa Dronabinol vs Placebo 48 (1 RCT)      SMD 0.47 lower
(0.89 lower to 0.05 lower)
Dronabinol vs Active 22 (1 RCT)      SMD 0.06 lower
(0.65 lower to 0.53 higher)
Anxiety Dronabinol vs Placebo 113 (4 RCTs) 49
LOW e
   SMD 0.03 lower
(0.47 lower to 0.41 higher)
Dronabinol vs Active 278 (1 RCT)      SMD 0.14 higher
(0.03 lower to 0.31 higher)
Nabilone vs Placebo 147 (6 RCTs) 84
VERY LOW a,c,e
   SMD 0.59 lower
(1.4 lower to 0.22 higher)
Nabilone vs Active 192 (2 RCTs) 11
LOW e
   SMD 0.11 lower
(0.33 lower to 0.11 higher)
Cannabidiol vs Placebo 481 (11 RCTs) 78
VERY LOW c,e
   SMD 0.34 lower
(0.73 lower to 0.06 higher)
Nabiximols vs Placebo 258 (6 RCTs) 43
LOW e
   SMD 0.06 higher
(0.23 lower to 0.34 higher)
Dementia Dronabinol vs Placebo 115 (3 RCTs) 3
LOW e
   SMD 0.27 lower
(0.57 lower to 0.04 higher)
Nabilone vs Placebo 76 (1 RCT)      SMD 0.53 lower
(0.87 lower to 0.19 lower)
Depression Dronabinol vs Placebo 700 (7 RCTs) 83
LOW c,f
   SMD 0.15 lower
(0.49 lower to 0.19 higher)
Dronabinol vs Active 278 (1 RCT)      SMD 0.14 higher
(0.03 lower to 0.31 higher)
Nabilone vs Placebo 76 (3 RCTs) 0
LOW e
   SMD 0.03 lower
(0.48 lower to 0.43 higher)
Nabilone vs Active 192 (2 RCTs) 0
LOW e
   SMD 0.03 lower
(0.23 lower to 0.17 higher)
Cannabidiol vs Placebo 301 (6 RCTs) 0
LOW e
   SMD 0.12 higher
(0.09 lower to 0.34 higher)
Nabiximols vs Placebo 413 (7 RCTs) 43
MODERATE f
   SMD 0.12 lower
(0.36 lower to 0.13 higher)
PTSD Dronabinol vs Placebo 46 (1 RCT)      SMD 0.63 lower
(1.22 lower to 0.03 lower)
Nabilone vs Placebo 18 (1 RCT)      SMD 0.88 lower
(1.65 lower to 0.11 lower)
Schizophrenia
/psychosis
Dronabinol vs Placebo 26 (1 RCT)      SMD 0.89 higher
(0.25 higher to 1.53 higher)
Cannabidiol vs Placebo 152 (3 RCTs) 70
VERY LOW c,f
   SMD 0.24 lower
(0.81 lower to 0.33 higher)
Cannabidiol vs Active 39 (1 RCT)      SMD 0.05 higher
(0.58 lower to 0.68 higher)
Sleep Dronabinol vs Placebo 683 (7 RCTs) 64
LOW c,f
   SMD 0.13 lower
(0.39 lower to 0.12 higher)
Dronabinol vs Active 22 (1 RCT)      SMD 1.12 higher
(0.37 higher to 1.87 higher)
Nabilone vs Placebo 175 (6 RCTs) 77
VERY LOW c,g
   SMD 0.58 lower
(1.14 lower to 0.01 lower)
Nabilone vs Active 200 (2 RCTs) 91
VERY LOW d,e
   SMD 0.21 lower
(0.97 lower to 0.55 higher)
Cannabidiol vs Placebo 961 (8 RCTs) 46
LOW a,c
   SMD 0.06 lower
(0.23 lower to 0.11 higher)
Nabiximols vs Placebo 3659 (23 RCTs) 61
MODERATE c
   SMD 0.24 lower
(0.35 lower to 0.14 lower)
SUDs Dronabinol vs Placebo 196 (3 RCTs) 0
LOW a,g
   SMD 0.47 lower
(0.73 lower to 0.2 lower)
Dronabinol vs Active 60 (1 RCT)      SMD 0.85 lower
(1.41 lower to 0.29 lower)
Nabilone vs Placebo 70 (3 RCTs) 0
LOW a,g
   SMD 0.55 lower
(0.93 lower to 0.18 lower)
Cannabidiol vs Placebo 353 (7 RCTs) 81
VERY LOW c,e
   SMD 0.2 lower
(0.63 lower to 0.24 higher)
Nabiximols vs Placebo 237 (4 RCTs) 59
MODERATE g
   SMD 0.48 lower
(0.92 lower to 0.04 lower)
Tourette Dronabinol vs Placebo 41 (2 RCTs) 0
MODERATE g
   SMD 1.01 lower
(1.58 lower to 0.44 lower)
Retention Dronabinol vs Placebo 3285 (37 RCTs) 65
LOW c,f
OR 1.11
(0.80 to 1.53)
194 per 1.000 17 more per 1.000
(33 fewer to 75 more)
Dronabinol vs Active 1079 (8 RCTs) 32
VERY LOW a,e
OR 1.03
(0.76 to 1.40)
422 per 1.000 7 more per 1.000
(65 fewer to 83 more)
Nabilone vs Placebo 1070 (16 RCTs) 0
VERY LOW a,e
OR 0.99
(0.76 to 1.29)
143 per 1.000 1 fewer per 1.000
(30 fewer to 34 more)
Nabilone vs Active 1004 (13 RCTs) 0
VERY LOW a,e
OR 0.99
(0.79 to 1.25)
205 per 1.000 2 fewer per 1.000
(36 fewer to 39 more)
Cannabidiol vs Placebo 1775 (22 RCTs) 41
VERY LOW c,g
OR 1.38
(0.77 to 2.47)
71 per 1.000 24 more per 1.000
(15 fewer to 88 more)
Nabiximols vs Placebo 4643 (33 RCTs) 44
LOW c,f
OR 1.17
(0.92 to 1.49)
170 per 1.000 23 more per 1.000
(11 fewer to 64 more)
Adverse events Dronabinol vs Placebo 2707 (37 RCTs) 56
LOW c
OR 2.16
(1.59 to 2.94)
320 per 1.000 184 more per 1.000
(108 more to 260 more)
Dronabinol vs Active 925 (8 RCTs) 67
LOW a,c
OR 2.75
(1.43 to 5.26)
466 per 1.000 240 more per 1.000
(89 more to 355 more)
Nabilone vs Placebo 996 (16 RCTs) 76
MODERATE c
OR 3.12
(1.52 to 6.42)
226 per 1.000 251 more per 1.000
(81 more to 426 more)
Nabilone vs Active 909 (13 RCTs) 71
LOW a,c
OR 2.47
(1.45 to 4.20)
223 per 1.000 192 more per 1.000
(71 more to 324 more)
Cannabidiol vs Placebo 1736 (22 RCTs) 58
MODERATE c
OR 1.82
(1.08 to 3.07)
482 per 1.000 147 more per 1.000
(19 more to 259 more)
Nabiximols vs Placebo 4404 (33 RCTs) 74
MODERATE c
OR 1.97
(1.48 to 2.64)
536 per 1.000 159 more per 1.000
(95 more to 217 more)
  1. *The basis for the assumed risk (e.g. the median control group risk across studies) is provided in footnotes. The risk difference (and its 95% confidence interval) is based on the assumed risk in the comparison group and the relative effect of the intervention (and its 95% CI). CI confidence interval, OR odds ratio. aModerate-High risk of bias; bMany high risk of bias; cModerate-Substantial heterogeneity; dHigh heterogeneity; eOptimal information size not met, CI overlaps no effect; fOptimal information size met, CI overlaps no effect; gOptimal information size not met, CI excludes no effect