Not bipolar and no past child abuse but I suffered a three year long depression that ended 10 years ago. I have had depressed moods before and after, but that one was very special. One of my main symptoms was I was completely dumb. I didn't understand how to manage anything. Had no sense of time. My attention span was so short I couldn't transfer things I thought into memory.

Needless to say I got in a bit of trouble, especially with unpaid bills. I forgot what to do with letters I got and what they were for. Also when I was downtown once (for an emergency appointment turning out I didn't need help here and now ironically enough) I forgot where I lived, and I had lived at the same place for five years. I was emotionally exhausted and could blow up at people for no reason.

When I got better I noticed my brain didn't work the same as before. I had actually became fearless (not anxiety less), my taste in music had changed radically, I had a much shorter attention span and I am dumber. Things are better than when I was really depressed but I took the same official test and I lost almost 10 IQ points.

I think depression can actually harm your brain but it can repair itself. It's just that it might not go back to where it was.