This observational study of 279 patients was published in the Journal of Cannabis Research in June 2021. It examined the effect of CBD-rich treatments on pain, anxiety, depression symptoms, and wellbeing.
The findings seem to demonstrate the biphasic nature of some cannabinoids. The CBD treatment was effective, but only with patients with moderate to severe symptoms. Those with mild symptoms did not experience improvement.
"This retrospective observational study suggests CBD-rich treatment has a beneficial impact on pain, anxiety, and depression symptoms as well as overall wellbeing only for patients with moderate to severe symptoms; however, no observed effect on mild symptoms."
The full paper is here.