Table 1.
Medical cannabis study efficacy outcome findings,1 by condition and study design type
| Total studies | Improvement | Worsening | Mixed | No change | Inconclusive | |
|---|---|---|---|---|---|---|
| ALS | ||||||
| Outcomes: cramp intensity and cramp frequency | 2 | − | − | − | 1 | 1 |
| Systematic reviews | 2 | − | − | − | 1 [11] | 1 [12] |
| Autism | ||||||
| Outcome: symptom mitigation | 3 | 2 | − | − | 1 | − |
| Observational or quasi-experimental studies | 3 | 2 [16, 17] | − | − | 1 [15] | − |
| Cancer | ||||||
| Outcome: pain | 13 | 5 | − | − | 2 | 6 |
| Systematic reviews with meta-analysis | 4 | 2 [24, 25] | − | − | − | 2 [220, 221] |
| Systematic reviews | 6 | 2 [28, 222] | − | − | − | 4 [32, 33, 223, 224] |
| RCTs | 2 | − | − | − | 2 [34, 225] | − |
| Observational or quasi-experimental studies | 1 | 1 [36] | − | − | − | − |
| Outcome: nausea and vomiting | 2 | 1 | − | − | − | 1 |
| Systematic reviews with meta-analysis | 1 | − | − | − | − | 1 [221] |
| Observational or quasi-experimental studies | 1 | 1 [36] | − | − | − | − |
| Outcome: cachexia | 3 | 1 | − | − | − | 2 |
| Systematic reviews with meta-analysis | 2 | − | − | − | − | 2 [37, 221] |
| Observational or quasi-experimental studies | 1 | 1 [36] | − | − | − | − |
| Chronic noncancer pain | ||||||
| Outcomes: pain reduction/quality of life | 17 | 10 | − | 1 | 3 | 3 |
| Systematic reviews with meta-analysis | 6 | 6 [25, 111, 113, 114, 115, 226] | − | − | − | − |
| Systematic reviews | 8 | 2 [121, 122] | − | 1 [42] | 2 [116, 117] | 3 [119, 120, 223] |
| Observational or quasi-experimental studies | 3 | 2 [227, 228] | − | − | 1 [118] | − |
| Crohn's disease | ||||||
| Outcome: symptom mitigation | 3 | 1 | − | 1 | − | 1 |
| Systematic reviews | 1 | − | − | − | − | 1 [131] |
| Observational or quasi-experimental studies | 2 | 1 [229] | − | 1 [61] | − | − |
| Epilepsy | ||||||
| Outcomes: frequency/duration of seizures | 19 | 13 | − | − | 4 | 2 |
| Meta-analysis only | 3 | 2 [137, 138] | − | − | 1 [230] | − |
| Systematic reviews | 2 | 2 [116, 143] | − | − | − | − |
| RCTs | 2 | 2 [136, 145] | − | − | − | − |
| Observational or quasi-experimental studies | 12 | 7 [134, 135, 139, 140, 141, 142, 144] | − | − | 3 [144, 146, 147] | 2 [149, 150] |
| Outcomes: health-related quality of life | 2 | 2 | − | − | − | − |
| Observational or quasi-experimental studies | 2 | 2 [144, 146] | − | − | − | − |
| Glaucoma | ||||||
| Outcome: intraocular pressure | 1 | − | − | − | 1 | − |
| Systematic reviews | 1 | − | − | − | 1 [116] | − |
| HIV/AIDS | ||||||
| Outcome: symptom mitigation | 2 | 1 | − | − | − | 1 |
| Systematic reviews with meta-analysis | 2 | 1 [120] | − | − | − | 1 [115] |
| Outcome: adherence to ART | 5 | − | 2 | − | 2 | 1 |
| Systematic reviews | 1 | − | − | − | − | 1 [231] |
| Observational or quasi-experimental studies | 4 | − | 2 [172, 232] | − | 2 [160, 173] | − |
| Outcome: viral suppression | 2 | − | − | − | 1 | 1 |
| Systematic reviews | 1 | − | − | − | 1 [231] | |
| Observational or quasi-experimental studies | 1 | − | − | − | 1 [173] | − |
| MS | ||||||
| Outcome: spasticity and spasm frequency | 6 | 3 | − | 1 | 1 | 1 |
| Systematic reviews with meta-analysis | 3 | 1 [179] | − | 1 [233] | 1 [183] | − |
| Systematic reviews | 3 | 2 [180, 181] | − | − | 1 [223] | |
| Outcome: pain | 4 | 1 | − | − | 1 | 2 |
| Systematic reviews with meta-analysis | 2 | − | − | − | 1 [183] | 1 [115] |
| Systematic reviews | 2 | 1 [180] | − | − | 1 [223] | |
| Outcome: bladder function | 3 | 2 | − | − | 1 | − |
| Systematic reviews with meta-analysis | 2 | 1 [184] | − | − | 1 [183] | − |
| Systematic reviews | 1 | 1 [180] | − | − | − | − |
| Outcome: gait and physical functioning | 1 | − | − | − | − | 1 |
| Systematic reviews | 1 | − | − | − | − | 1 [185] |
| Parkinson's disease | ||||||
| Outcome: none assessed | − | − | − | − | − | − |
| PTSD | ||||||
| Outcome: symptom mitigation | 8 | − | − | 2 | − | 6 |
| Systematic reviews | 8 | − | − | 2 [192, 193] | − | 6 [12, 122, 194, 195, 197, 234] |
ALS, amyotrophic lateral sclerosis; HIV, human immunodeficiency virus; PTSD, posttraumatic stress disorder; RCT, randomized controlled trial; MS, multiple sclerosis. 1 Findings for efficacy outcomes were classified for cannabis/cannabinoid treatment relative to placebo or active comparator according to the following: “improvement” if outcome improved, “worsening” if outcome worsened, “mixed” if multiple efficacy outcomes were assessed with divergent findings for each, “no change” if no change observed, and “inconclusive” if outcomes were unable to be assessed.