Many people have been wondering what Abby's history consists of, and this screenshot is Abby herself admitting that she is bipolar. Because of her bipolar disorder, she says that she can't stand the paranoia that comes out of smoking weed (however I do believe Abby herself mentioned that she smokes cigarettes).
Abby has also more recently started wearing shorter pants, showing her scars from previous self harm. Abby herself has mentioned that she attempted suicide. Before her "Rat Nest" phase, any photo of her legs that displayed self harm were covered up with stickers of Jack Skellington.