Here is great article by a great Doctor Lady, Felecia L. Dawson, M.D.
"In 2004, Dr. Ethan Russo hypothesized that some people have disease due to an underperforming ECS. This can be due to lifestyle, diet, genetics, trauma, etc. He coined this, “Clinical Endocannabinoid Deficiency Syndrome (CEDS).” Typically, one component of the ECS is abnormal or present in abnormal amounts. For example, research has shown that people who have migraines or PTSD are deficient in endocannabinoids compared to those who do not have these conditions. Other examples of CEDS include autoimmune disease, PMS, painful menstrual periods, endometriosis, neurodegenerative disorders (e.g. Alzheimer’s Disease, Parkinson’s Disease), mood disorders (e.g. anxiety, depression, PTSD), ADD/ADHD, seizures, cancer and chronic pain. Thus, people with these conditions may feel better when they use cannabis or CBD. They are self-medicating." Here's the list: