Is MPB caused from prescribed antidepressant use on a person without family history of MPB more aggressive and less treatable than MPB caused from natural occurrence?
Male pattern baldness (MPB) is from genetic causes. You may not have a noticeable family history of MPB, but it can skip generations… and you do not get it from prescription medication. MPB is generally treatable with medications such as Propecia (finasteride) or Rogaine (minoxidil).
As for hair loss caused by medication, as long as you are on the offending drug, the hair loss will not reverse. It may not reverse at all, even if you stop the medication. Some people get better from withdrawal of the drug and others do not. There is no way to compare this problem (worse or better) with genetic hair loss.