Dorothy Mills (2008) on Netflix

Jane Morton, a psychiatrist from Dublin in deep mourning following the accidental death of her husband and son, is assigned to work on the case of Dorothy Mills, a teenaged girl in a small village who tried to strangle a baby. After miraculously surviving a car accident, Jane discovers a village darkened by strange events and meets a very nervous Dorothy, who swears she never touched the baby. After analyzing the teenager, Jane makes a diagnosis of multiple personality disorder until the day that Dorothy speaks with the voice of David, Jane's dead son.