Therapist

The Sim Shrink is an NPC that comes to your Sims when they go into aspirational failure (Aspiration bar in total red). He examines the Sims and helps them getting back a little of their Aspiration Bar, then he disappears again. The Therapist is just a mirage by Sims in aspirational failure and does not exist.

The shrink can only be seen by the Sim that he is taking care of. But Sims in the same room will turn to the Sim being helped and do the 'You're Crazy!' sign.

Using cheats, you can add the Sim Shrink to your family, but he shows up for a few seconds and is not seen again on the lot, but still in Sim menus and family description, and it is quite irritating as you can't get rid of him, and if you try to kill him with the death creator, he won't die as he doesn't appear in a physical form. The plumb-bob appears next to the tombstone of L and D (or whatever you used to summon him) and is frozen in that spot.