Potency of THC and curing disabilities?

so people have been going around saying things and well seeming as im an every day pot smoker i decided to get into the conversation a bit. Now this is just a small debate between everyone in my school, even the people who dont smoke ****. They say that there is a potency problem with "high grade" medical pot. That even high grade wont **** you up or help slow the problem. Heres what i have to say. If its smoke-able and recommended by your doctor, veer away from high and low grade, stay somewhere in the center, because even if you wanna get ****** up or just get a buzz, medium weed will help fix your problem and get you high. but what people are telling me is that the higher the potency the worst time your gonna have curing your disability, while others are saying it cures them quicker. So even though i know if you wanna cure your problem quicker and get higher, purchase the middle amount, i wanna know what you "professional" pot smokers or doctors have to tell me. What do you think, answer me please. I just wanna see how stupid some ppl are