Dr. Anne Sullivan (Annabeth Gish) is back in Rosewood during Pretty Little Liars Season 3B, and we're far from convinced that's good news for the girls.

Dr. Sullivan seems well intentioned, and she certainly did come off as freaked by Mona (Janel Parrish) in Season 3, Episode 18: "Dead to Me" but we all know that no one can be trusted in Rosewood. This psychiatrist sets off warning bells for us, and that's more true than ever now that we know Toby (Keegan Allen) is on the "A" team.

Here are four reasons we don't trust Dr. Sullivan.

1. Toby is the one who brought her back. In Season 2 Dr. Sullivan disappeared, only to be brought back to Rosewood just in time for Mona's (Janel Parrish) capture. Who brought her back? Oh, you know, just Toby (Keegan Allen). Given that Toby is part of the "A" team, we feel like this can't be a coincidence. And if it's not a coincidence, it very well might mean Dr. Sullivan was working to help the "A" team.
 
2. Blackmail. In Season 2 we saw Dr. Sullivan being threatened by "A", so it seems hard to believe she's actively part of the "A" team (unless the main "A" was punishing her for being out of line?). However, she also admitted to the girls that "A" was blackmailing her into staying away, by threatening her son. She claimed Toby's courage inspired her to come back anyway, but now that we know Toby is part of the "A" team, we have to wonder if maybe she was still under duress when she said that. Perhaps she was moved less by Toby's bravery than by his threats. If so, she very well could still be under the "A"' team's thumb.

This theory might also explain her reaction to seeing Mona in Episode 18 — if she's still being threatened by the "A" team, of course she wouldn't want Mona at her door.

3. She's the one who diagnosed Mona. Dr. Sullivan was the person who diagnosed Mona with the personality disorder that landed her in Radley instead of jail. As we've seen this season, Mona could still do a lot of damage from inside Radley's walls, and it didn't take her long to get released. Was Dr. Sullivan purposefully doing her a favor when she declared her insane?

4. Emily's dream. Dr. Sullivan is the one that convinced Emily (Shay Mitchell) to try hypnotherapy, which ended up with her thinking she'd killed Alison (Sasha Pieterse). Could Sullivan have purposefully been messing with Emily, or trying to get information out of her?

Some people have actually speculated that Dr. Sullivan is Toby's mom (who, yes, is supposedly dead, but hey, that could be a lie), which would add a whole new level to the idea that her son is being blackmailed.

What do you think? Can we trust Dr. Sullivan? Let us know in the comments below.

Catch the next new episode of Grey’s Anatomy on Thursday, February 7, 2013, at 9 p.m. ET/PT on ABC.

Rebecca Martin is an editor at Wetpaint Entertainment. Follow her on Twitter @BeccaDMartin.