All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad, sallallaahu ‘alayhi wa sallam, is His slave and messenger.
It is permissible to take the medication prescribed by a non-Muslim doctor or otherwise if he is reliable and honest, whether it is a psychoactive medication or something else. Ibn Muflih said, “Shaykh Taqiyy Ad-Deen (Ibn Taymiyyah) wrote, ‘If a Jewish or Christian doctor is believed to be trustworthy by the patient, it is permissible for him to seek medical treatment from him just as it is permissible for him to deposit money with him or conduct transactions with him... However, if it is within his ability to consult a Muslim doctor, he should not leave him and go to a non-Muslim, just as the case with depositing and conducting transactions. However, if the person needs to entrust a non-Muslim doctor or seek his medical help, it is allowable.’”
Hence, there is no problem in seeking medical treatment from a Muslim doctor who commits religious violations as seeking medical treatment from him is more permissible, with greater reason, than seeking treatment from a non-Muslim doctor, whom the patient believes to be trustworthy and reliable.
Allaah Knows best.