Table 2. Summary of eligible studies.
| Reference | Year, Country | Study design, Total sample size | Interventions, sample size per group | Delivery | Tx duration | Washout period for crossover studies | Gender (M/F) | Age (Mean ± SD or range in years) |
|---|---|---|---|---|---|---|---|---|
| Abrams, et al. 2007 [63] | 2007, USA |
DBRPCT parallel design N = 55 |
∙ 3.56% THC cigarettes (n = 27) ∙ 0% THC cigarettes (n = 28) |
Smoked | 5 d | N/A | 48M/7F | Tx group: 50 ± 6 Placebo 47 ± 7 |
| Almog, et al. 2020 [47] | 2020, Israel |
Crossover DBRPC N = 27 |
∙ 0.5 mg single inhalation of Δ9-THC ∙ 1 mg single inhalation of Δ9-THC ∙ 0% THC Placebo matched |
Inhaler | 3 x 150 min sessions | 2 d washout | 8F/19M | 48.3 ± 11.9 |
| Berman, et al. 2004 [49] | 2004, England |
DBRPCT Crossover N = 48 |
∙ Sativex (THC 2.7 mg & CBD 2.5 mg per 100 mL) spray ∙ 2.7 mg THC oromucosal spray ∙ Placebo spray |
Spray | 14 d | No washout | 46M/2F | Mean: 39 23-63 |
| Eibach, et al. 2020 [48] | 2020, German |
RDBPC Crossover N = 32 |
∙ 400 mg/daily oral dose CBDV dissolved in sesame oil ∙ Identical appearing placebo dissolved in sesame oil |
Oil | 4 weeks | 3 weeks washout | 31M/1F | CBDV: 52.31 ± 8.06 36-65 Placebo: 48.31 ± 9.62 31-65 |
| Ellis, et al. 2009 [56] | 2009, USA |
DBRPCT Crossover N = 34 |
∙ 1% to 8% THC cigarettes 5xday ∙ Placebo cigarettes 5Xday |
Smoked | 5 d | 2 weeks washout | 34M/0F | 48.8 ± 6.8 |
| Karst, et al. 2003 [57] | 2003, Germany |
Crossover study N = 21 |
∙ CT-3, 10 mg oral capsules (synthetic THC analog without the psychotropic effects) ∙ Placebo capsules |
Oral capsules | 1 week washout | 1 week | 13M/8F | 29-65 |
| Nurmikko, et al. 2007 [58] | 2007, UK & Belgium |
DBRPCT parallel N = 125 |
∙ Sativex (THC 2.7 mg & CBD 2.5 mg per 100mL) spray (n = 63) #x2219; Placebo spray (n = 62) |
Spray | 5 weeks | N/A | 50M/74F (one patient censored) |
Tx group: 52.4 ± 15.8 Placebo: 54.3 ± 15.2 |
| Selvarajah, et al. 2010 [50] | 2010, United Kingdom |
DBRPCT parallel N = 29 |
∙ Sativex (THC 2.7 mg & CBD 2.5 mg per 100mL) spray (n = 15) ∙ Placebo spray (n = 14) |
Spray | 10 weeks | N/A | 18M/11F | Tx group: 58.2 ± 8.8 Placebo: 54.4 ± 11.6 |
| Serpell, et al. 2013 [61] | 2013, United Kingdom, Czech Republic |
DBRPCT parallel N = 246 |
∙ Sativex (THC 2.7 mg & CBD 2.5 mg per 100mL) spray (n = 128) ∙ Placebo spray (n= 118) |
Spray | 14 weeks | N/A | 96M/150F | Tx group: 57.6 ± 14.4 Placebo: 57.0 ± 14.1 |
| Svendsen, et al. 2004 [51] | 2004, Denmark |
RDBPCT Crossover N = 24 |
∙ Dronabinol 2.5 mg capsules (n = 24) ∙ Placebo sesame seed oil capsule (n = 24) |
Oral capsules | 18-21 d | 21 d | 10M/14F | Median: 50 23-55 |
| Wade, et al. 2002 [60] | 2002, United Kingdom |
DBRPC Crossover N = 20 |
∙ 2.5 mg THC & 2.5 mg CBD spray ∙ 2.5 mg THC spray ∙ 2.5 mg CBD spray ∙ Placebo spray |
Spray | 2 weeks | None | 10M/10F | Mean: 48 |
| Wallace, et al. 2015 [52] | 2015, USA |
DBRPC Crossover N = 16 |
∙ 7% THC Vaporized cannabis ∙ 4% THC Vaporized cannabis ∙ 1% THC Vaporized cannabis ∙ 0% Vaporized cannabis |
Vaporized | 4 x 4 hours | 2 week | 9M/7F | 56.9 ± 8.2 |
| Ware, et al. 2010 [62] | 2008, USA |
RDBPCT Crossover N = 23 |
∙ 2.5% THC ∙ 6.0% THC ∙ 9.4% THC ∙ Placebo 0% THC |
Inhaled - pipe | 5 d | 9 d | 11M/12F | 45.4 ± 12.3 25–77 |
| Wilsey, et al. 2008 [53] | 2008, USA |
RDBPC Crossover N = 38 |
∙ 7% THC ∙ 3.5% THC ∙ 0% THC |
Inhaled cigarettes | 3 x 6-hour sessions | 3 d | 20M/18F | Mean: 46 21-71 |
| Wilsey, et al. 2013 [54] | 2013, USA |
DBRPCT Crossover N = 39 |
∙ 3.53% THC ∙ 1.29% THC ∙ Placebo cannabis |
Inhaled vapor | 3 x 6-hour sessions | 3 d | 28M/11F | 50 ± 11 |
| Wilsey, et al. 2016b [55] | 2016, USA |
DBRPCT Crossover N = 42 |
∙ 0% delta 9-THC, ∙ 2.9% delta 9-THC ∙ 6.7% delta 9-THC |
Inhaled vapor | 3 x 8-hour sessions | 3 d | 29M/13F | 46.4 ± 13.6 |
| Wilsey, et al. 2016a [59] | 2016, USA |
RPCT Crossover N = 42 |
∙ 6.7% THC cannabis ∙ 2.9% THC cannabis ∙ 0% THC cannabis |
Inhaled vapor | 3 x 8-hour sessions | 3 d | 29M/13F | Mean: 46.4 |
Abbreviations: CBD, cannabidiol; CBDV, cannabidivarin; CRPS, Complex Regional Pain Syndrome; d, day; DBRPCT, Double-blind Randomized Placebo-Controlled Trial; F, female; N, participants; n, participants; NP, Neuropathic pain; M, male; RPCT, Randomized Placebo-Controlled Trial; THC, tetrahydrocannabinol; y, years.