Our expert says:

CyberShrink

I'm not sure what you mean by "regular" PND. If you mean "ordinary" PND, then one would expect it to be successfully treated when it occurs, and not usually to last for 5 years, though it can recur in a subsequent pregnancy. And one can't be "eact" about a hypothetical case. If anyone's depression, whether PND or any other variety, gets severe enough or complex enough to seriously be a risk to their lives or continued wellness, a hospital admission might be recommended --- so they can be properly observed by the staff, so a new form of medication could be tried and its effects more closely monitored, whatever. The purpose of any proposed hospital admission ought to be explained to any prospective patient and their family, at the time.
And yes, one can overcome Depression. Personally, I believe the best approach to treatment would usually involve medication with properly selected antidepressants AND Cognitiver-Behaviour Therapy ( CBT ) which is very effective in treating Depression and in helping you to learn how to keep it under control.