Tutti i colori del buio, All the Colors of the Dark (1972) Sergio Martino

Jane lives in London with her boyfriend Richard. Her mother was murdered when she was young, she recently lost a baby in a car crash and shes plagued by nightmares of a knifewielding man. Richard thinks that the cure is vitamins, while Janes sister recommends psychiatric help. But a new neighbour promises that if she participates in a Black Mass, all her fears will disappear, instead it just seems to bring her nightmares to life.