It's not only psych meds that are tricky. My friend and I have different autoimmune illnesses. Hers didn't get better with just high dosage steroids so they had to add a cancer med. It didn't go that well. They tried some med on me that is supposed to regulate the immune system but it didn't do anything at all for me! So I opted out of treatment.

Also many people struggle to find a med that keeps blood pressure under control, and some blood pressure meds are thought to CAUSE heart issues and cancer. So everything is not fine and dandy on the somatic side of things either.