I didn't think they could but apparently they can to other doctors for treatment purposes just under HIPPA.

Does the HIPAA Privacy Rule permit doctors, nurses, and other health care providers to share patient health information for treatment purposes without the patient?s authorization?

They mostly can't tell other people like family members unless you are considered incompetent or dangerous to self or others which is sometimes the case with mental illness. Your therapy notes but not diagnosis and treatment have further protections so yes if you told them who your new doc is then they might transfer your meds and dx but not their thoughts that they wrote in therapy notes.

I honestly thought they couldn't because I've always had to sign something but that seems to be state legislated rather than federal. I will try to look up Texas laws for you.