I suffered this at the hand of my mom for more than 25 years until my own psychiatrist did a 'single-blind' test, found I had no signs of what others had diagnosed me with, and, after a year of carefully going over my case, concluded that I was indeed a victim.
That being said, I'll never forget how he clearly described it to me as more of a classic personality disorder than any 'true mental illness'. Here's almost a direct quote of what he told me:
[I'd just told him I'd heard of MBP, but didn't know much about it...then asked him if it was 'anything like hypochondria']
"No--hypochondriacs really are sufferers of a mental illness; they can't help what they're doing. They really do think something's always wrong with them, and have almost no control over the compulsion that something's always needing fixed, whether it's in their heads, or some physical ailment."
"Your mother knew exactly what she was doing the whole time she did it. Munchausens by Proxy is using someone else to further your own ego--to make yourself feel superior, to validate--even massage--their ego, no matter how much they harm their victims. That's why it's a crime--it has nothing to do with that person's lack of self-esteem, although some quacks will try and get you to believe that."
"People who do this not only know exactly what they're doing--they also are fully aware it's wrong; this is why most cases of it are correctly pursued as criminal cases, to make these people accountable for what they've done to others, because, believe me, if they aren't forced to be accountable, they will never admit they've hurt their victim or victims. She's also a classic narcissist, as most of them are, which means as long as you live you'll never hear her apologize for hurting you, almost ruining your life...controlling you, not once. She'll go to her grave thinking she was not only okay doing that, but, if allowed, she'd do it all over again, every time, and be gratified for doing the things she did."
That was over a decade ago, and that guy is still right to this day, on every count.