Table 3. Outcomes, results, and limitations of the selected RCTs.

HRV: Heart Rate Variability; CPM: Conditioned Pain Modulation; COVAS: Computerized Visual Analog Scale; NPS: Neuropathic Pain Scale; VAS: Visual Analog Scale; NMS:  National Medical Services; FIQ: Fibromyalgia Impact Questionnaire; THC: Tetrahydrocannabinol

Author, Year of Study	Outcome	Results	Limitations
Weizman et al. 2018 [12]	Pain assessment on visual analog scale (VAS); functional brain connectivity	THC-induced analgesia correlates with reduction in functional connectivity between the anterior cingulate cortex and sensorimotor cortex.	Exclusion of women; size of the study population
Xu et al. 2020 [13]	Pain modulation based on neuropathic pain scale (NPS)	Reduced sharp pain; no significant reduction in dull pain	Size of study population; chronic pain experienced from peripheral neuropathy of different etiologies was included in the study.
Weizman et al. 2024 [14]	Assessment of parasympathetic autonomic tone through heart rate variability (HRV) indices; supraspinal pain modulation determined from conditioned pain modulation (CPM) response using computerized visual analog scale (COVAS)	Post-THC administration there is a decrease in HRV indices reflecting a shift toward parasympathetic dominance. This implies reduction in chronic pain which is often associated with sympathetic dominance. Higher reduction in experienced pain through improved CPM response	Exclusion of women; size of the study population; before inclusion in the study, patients were tested for neither cannabinoids nor any other drug abuse
Almog et al. 2020 [15]	Assessment of pharmacokinetics of the drug by doing cannabinoid analysis of the blood samples at NMS Labs; measurement of the pain intensity using VAS.	There was a marked decrease in the VAS score for pain with 1.0 mg of THC as compared to 0.5 mg and placebo. Pain was also noted to decrease more with 0.5 mg of THC as compared to placebo. A notable decrease in pain was observed from 15 minutes and up to 120 minutes after inhalation of THC.	The study tested only single dose effects and not effects over the long term in a small sample size. Only two different low doses (0.5mg, 1.0mg) of the drug were tried. A single type of cannabis drug, one that was high in THC and low in CBD was included in the trial.
Chaves et al. 2020 [16]	Assessment of symptoms and quality of life using FIQ scores	Significant reduction on FIQ scores; notable increase in energy levels for daily activities	Size of the study population; short intervention period; no inclusion of washout period