Adrianna was a college friend of Lianne Mars and helped Lianne during her recovery from the mental institute and helped her look for Keith and Veronica Mars.

Personal assistant to Lianne

She helped Lianne when she was on the run but wasn't told where she went next because she wouldn't be able to keep a secret from Keith Mars. When Veronica Mars tracked her mother to Adrianna's house, Adrianna assured her that Veronica was all Lianna thought about. Veronica wasn't convinced. (Meet John Smith)