A Woman's Torment (1977) [1080p]

A young woman experiences severe mental distress, leading her to hallucinate and engage in violent behavior. A wealthy couple, Don and Frances, face challenges in their marriage, exacerbated by the presence of Frances's mentally ill sister, Karen, who has become mute since moving in with them. The couple struggles to decide what to do with Karen, seeking advice from their psychologist friend Otis and his discontented wife Estelle.

Upon learning that they are considering committing her to an asylum, Karen escapes to an abandoned beach house on Fire Island. There, she undergoes a series of intense sexual experiences that amplify her inner turmoil, ultimately resulting in violent actions driven by the voices in her head.