Anne Sullivan

Dr. Anne Sullivan is the therapist, who is chosen by the girls' parents to help them deal with their seemingly obsessive thoughts about pinning Alison's murder on Ian. She does not try to push the girls, rather only to win their trust in order to help them heal.

Season 2
We first meet Dr. Sullivan in the episode, "It's Alive" during her first session with the girls. In her office, Spencer, Aria, and Emily sit silently. Hanna walks in late, hoping to have missed the whole appointment, but to her annoyance, the girls have ‘politely’ waited for her. When they finally do get to talking, they speak minimally. Aria is the most tempted to confide in the inviting Dr. Sullivan, especially about that thing, but their cellphones go off, scaring them with reminders of "A" finding anything out. They leave, thereby leaving Dr. Sullivan completely in the dark.

Later, the girls discuss "A's" violent tendencies, and bring up Dr. Sullivan, who is sworn to confidentiality, and Emily and Aria are the loudest proponents in favor of cluing her in on their secrets. Spencer agrees, and even Hanna, the most unwilling to see a shrink, is in, as she approves of Dr. Sullivan’s fashion sense - a clear signal to Hanna about her character.

At Dr. Sullivan’s office, the girls are ready to tell all, until they catch sight of Ezra’s Bachelor certificate on the wall, a subtle hint from "A" that she is privy to everything they say. They had scheduled the appointment impromptu, yet they suddenly cancel, leaving Dr. Sullivan completely baffled and frustrated with the lack of communication. She had noticed that their decision to turn back, once on the brink of telling her, stemmed from one of the girls and slowly spread to the other four, but can’t figure out why. She believes that the girls are frustrating their attempts at therapy by coming as a group and so recommends to their parents to have them separate for a while, both within sessions and without.

At the end of that episode, she is seen walking from her office, onto the fact that she is being stalked, and frightened as a result.

Later, in "Blind Dates" she helps Hanna move on from Alison's mental haunting through catharsis and role play.

She returns in "Touched by an 'A'-ngel" to Rosewood High School in preparation of her upcoming speaking engagement. There, she bumps into Ella Montgomery, who confides in her about Mike's issues. Dr. Sullivan professionally tells Ella that she does not recommend siblings seeing the same therapist, and so, agrees to give her referalls.

Later, Dr. Sullivan spots Emily at her locker, struggling with some books that have fallen out and goes to assist her. She immediately picks up on Emily's anxiety vibes and offers to help her if only Emily will confide in her. Emily makes a confession that she has been hiding big things from Dr. Sullivan, who in turn, urges her to schedule and appointment and share her thoughts in her office. Emily nods, but later does not follow through.

After "A" terrifies Emily by giving her a massage, Emily contemplates dialing Dr. Sullivan, but hesitates after "A" sends a threatening text. Later, while Emily is being comforted by her friends regarding the incident, she ignores Dr. Sullivan's incoming call, not telling Hanna who it was. At the end of the episode, Dr. Sullivan is seen returning to a patient in her office, apologizing for having kept her waiting to call another patient. She then comments on being chilly and grabs a sweater off the coat rack, where a black hoodie is also hanging. She sits and asks the patient what she wants to discuss...clearly she is treating "A", but for how long is a mystery.

Trivia

 * Her name, Anne Sullivan is the same as Hellen Keller's famous mentor. Perhaps a connection in that she helps others optomize their potential.