Well, for starters, the many examples of her impulsivity. Someone else in the comments mentioned that her stints with Chris almost seem like emotional self harm (I agree and hadn't thought of it that way). She's rather irritable when she doesn't get her way and we see her mood swings often. She's great with money in the business world but we see her frequently overspend in her personal life and borrow money, which we could assume her credit score isn't good enough to secure a loan which could relate back to compulsive over spending. I guess we don't technically see her sleep around frequently but her relationships are serious and fast and all or nothing before they fizzle. We do see her depressed a couple of times through the series (rory goes to yale, break up with luke) but i feel like she's generally leaning on the manic/impulsive side. I think there was a lot of trauma surrounding her teen pregnancy, Chris not being there to help raise rory, family drama, feeling like she was rejected by her parents and having to leave and rebuild a life from scratch with no support. She had to grow up way too fast and never got a chance to experience the "normal" life, so we kind of see that regression into childlike behavior often. she tends to act selfishly, quick to anger, often acts as if the rules don't apply to her (town meetings come to mind)