There is reasonable evidence that cannabinoids improve nausea and vomiting after chemotherapy. They might improve spasticity (primarily in multiple sclerosis). There is some uncertainty about whether cannabinoids improve pain, but if they do, it is neuropathic pain and the benefit is likely small.
Link: Systematic Review Of Systematic Reviews For Medical Cannabinoids: Pain, Nausea And Vomiting, Spasticity, And Harms
Year: 2018
Probability toward demonstrable efficacy of cannabis for treatment of Pain (Neuropathies, in general) according to the results found in this study.
Probability toward demonstrable efficacy of cannabis for treatment of Chemotherapy-Induced Nausea and Vomiting according to the results found in this study.
Probability toward demonstrable efficacy of cannabis for treatment of Multiple Sclerosis (MS) according to the results found in this study.
A meta-analysis of 31 randomized controlled trials conducted on human patients.