The Possessed(1975)

A young psychiatrist, Eleni Stavrianou, with painful experiences after her psychopathic father killed her mother and then committed suicide, is treating young Christina, who suffers from severe schizophrenia. In her efforts to help her, she clashes with the girl's family, who believe that salvation can only come from God. Because of this mindset, the relatives try to cure the sick girl with exorcisms. With all this, of course, the patient's condition continues to worsen, but the doctor also begins to gradually lose her footing and feel her mental balance and spiritual clarity being disrupted, until she herself is driven to schizophrenia.