One of my few ADD friends has a pretty sharp tongue, she will tell you how much she loves you one minute and pretend like she doesn't know you the next.... Is this a personality trait or ADHD symptom?

For instance she blocked me because "i talk too much" and "we're not friends" although i'm just being a friend to her regardless of this. I know she will turn to me when her hyperfocus ends and she dumps her boyfriend as usual. So if she does this why does she block me, tell me i don't mean anything to her because she has other friends (all of which she is no longer friends with) so why does she say such extreme stuff when she doesn't seem to mean it?

Claire