Depression and Combative Behavior?

Hi,
I wanted to ask what the relationship is between depression and aggressive, nasty behavior. My girlfriend's parents may suffer from this. They are largely shut-ins, rarely work, have 12 dogs that they seldom walk anymore. All they ever talk about is their many "sicknesses" and "ailments", which I find bizarre and strange. I stopped talking to them about a year ago because they were continually outwardly nasty to me. I don't get it.

I guess I'm just curious as to where the aggression comes from.

Possibly. I thought my brother in law was just a nasty person until he went on antidepressants and got... well, not nice, but a lot less nasty. I was really angry all the time before I went on meds.

Thanks for that. I have heard the whole "rage turned inward" explanation, perhaps that is what is at play here. Adding to the equation is a 4-6 week period where they turn pleasant again, hook you in, then push you away again. It's odd and cyclical.