Researchers are studying whether medical marijuana can help treat several conditions including Alzheimer's disease, Appetite loss, Cancer, Crohn's disease, Diseases effecting the immune system like HIV/AIDS or Multiple Sclerosis (MS), Eating disorders such as anorexia, Epilepsy, Glaucoma, Mental health conditions like schizophrenia and posttraumatic stress disorder (PTSD), Multiple sclerosis, Muscle spasms, Nausea, Pain, Seizures, Wasting syndrome (cachexia).
Reference:
https://www.webmd.com/a-to-z-guides/medical-marijuana-faq#1-2