This was a prospective study of over 10,000 patients over three years from Israel's largest medical cannabis clinic that characterized the medical cannabis patient population as well as identified treatment adherence, safety, and effectiveness. It was published in Frontiers in Medicine in February 2022.
The study reported that the most common conditions addressed with medical cannabis in the clinic were cancer (49%) and non-specific pain (29%).
Over 70% of the patients had treatment success at 6 months. 34% reported side effects. The most common side effects reported were dizziness, dry mouth, increased appetite, sleepiness, and psychoactive effect.
"We observed that supervised medical-cannabis treatment is associated with high adherence, improvement in quality of life, and a decrease in pain level with a low incidence of serious adverse events."
The full-text research article is here at Frontiers in Medicine.