Sinthia: The Devil's Doll(1970)

Half child... but all woman. How abnormal can a girl be?

Cynthia Kyle enters puberty with a vengeance, murdering her parents as they make love: she's wanted her father to love only her. Eight years later, she's free and wants to marry, but nightmares plague her so she seeks psychiatric help. The doctor asks her to describe a dream: it's long and elaborate with dreams within dreams of Lucifer, Hell, and her parents in various guises. To shed her guilt, the shrink recommends that she commit suicide in her next dream. In it, she falls in love with an artist who reminds her of her father, responds to a woman who finds her attractive, and celebrates her first school-yard kiss. The dream takes her back to her parents' bedside. Is any cure possible?