Table 2.

Summary of the use of cannabinoids on neuropathic or pain or pain related to chronic pain diseases such as fibromyalgia or MS.

Author (y)	Groups Studied and Interventions	Results and Findings	Conclusions
Ware et al. (2010) [29]	Adults with post-surgical or post-traumatic neuropathic pain (>4 on VAS) for ≥ 3 months. Requirements: normal liver and renal function, hematocrit > 38%, negative pregnancy test. Exclusion criteria: cancer, severe comorbidity, substance abuse, history of psychosis, suicide, pregnancy, breastfeeding.	VAS pain scores for 9.4% THC were significantly reduced (9.4% THC = 5.4, 0% THC = 6.1, p = 0.023); 9.4% THC improved sleep quality and symptoms of anxiety and depression (p < 0.05 for both).	Smoked cannabis improved pain, mood, and sleep quality in chronic neuropathic pain.
Weizman et al. (2018) [32]	27–40-year-old men with chronic lumbar radicular pain for > 6 months. Women and patients with other comorbidities were excluded.	THC decreased ACC and sensorimotor cortex functional connectivity in right SII, left SII, and right MI, which correlated with improved pain (r = 0.68, p = 0.005; r = 0.66, p = 0.007; r = 0.8, p = 0.0003, respectively).	THC may reduce subjective neuropathic pain by interfering with neural pathways in the ACC.
van de Donk et al. (2019) [34]	Adult females with fibromyalgia and NRS pain score ≥ 5. Exclusion criteria included neuropsychiatric disorders, use of opioids or benzodiazepines, substance abuse, pregnancy, breastfeeding, recent cannabis use, pain disorder other than fibromyalgia.	No significant differences between groups for NRS pain scores or electrical pain threshold; 30% pain reduction in 18 bediol patients (p = 0.01). Bediol and bedrocan enhanced pressure threshold (p < 0.001 and p = 0.006, respectively).	Bedrocan and bediol reduced pressure threshold, but no group significantly reduced pain NRS scores or electrical pain threshold.
Chaves et al. (2020) [38]	Adults with fibromyalgia with moderate-severe symptoms. Exclusion criteria included comorbidity, psychiatric illness, another disorder causing pain, pregnancy, breastfeeding, cannabis sensitivity.	Significant decline in FIQ scores in the cannabis group (cannabis = 30.50 ± 16.18, placebo = 61.22 + 17.30, p = 0.005).	THC oil improved the quality of life in fibromyalgia patients.
Ware et al. (2010) [40]	Adult fibromyalgia patients with chronic insomnia for 6 months. Exclusion criteria: cancer, use of monoamine oxidase inhibitors, neuropsychiatric illness, urinary retention, or sensitivity to study drugs.	Nabilone was superior in sleep quality (difference = −3.25, 95% CI = −5.26 to −1.24). No significant differences on Leeds Sleep Evaluation Questionnaire, but nabilone showed more restful sleep (difference = 0.48, 95% CI = 0.01–0.95) and quicker sleep onset (difference = −0.7, 95% CI = −1.36–0.03).	Nabilone was effective in improving sleep quality in fibromyalgia patients with chronic insomnia.
van Amerongen et al. (2018) [44]	Adults with progressive MS and severe pain and spasticity. Patients were excluded if they had epilepsy, recent disease worsening, or severe cardiac, renal, or hepatic disease.	Improvement from baseline spasticity on Modified Ashworth Scale, 9-Hole Peg Test, and subjective NRS (p = 0.001, p = 0.018, and p = 0.001, respectively). No change in gait or H/M ratio from baseline. Prolonged CSP duration in MS patients (47.9 ± 6.2, p = 0.001).	Oral THC:CBD spray was effective in reducing spasticity in MS patients.