You really are very wrong here. My husband and I have been on several of the same medications and we DO respond completely differently. I was able to take lithium without serious side effect issues; lithium nearly killed my husband. I was able to take lamictal with absolutely no side effects and it worked well for my depression; my husband cannot take lamictal at all because it causes him severe memory and cognitive problems and has little effect on his mood. I can take seroquel xr, in fact prefer it, because it doesn't overly sedate me during the day like regular seroquel does; if my husband takes one seroquel xr, it knocks him unconscious for 24 hours--he takes regular seroquel with no sedation issues at all during the day.

Even simple allergy and cold medications affect people differently. Most people prefer to take a cold or allergy med with a decongestant, but anything with a decongestant in it creates insomnia in me. Can't touch the stuff.

People really are that different in how they react to medications. What works well for one may do absolutely nothing or cause severe side effect issues in another.