One of the best suspense films of the 1940's neither directed by Alfred Hitchcock nor produced by Val Lewton, "The Spiral Staircase" is the story of a young woman who was frightened so much as a child by the loss of her parents that she cannot speak a word.
She comes to care for an older bedridden woman (Ethel Barrymore) who lives in a creepy mansion in early 20th Century New England. A grown step-son who is a college professor and another son who is a odd and lasivious character also are at the mansion, along with an assortment of other servants and nurses.
A series of murders of young women with physical afflictions is taking place in the local town. The constable believes the killer may be hiding near the mansion in question. One dark and stromy night later, all is revealed.
Elsa Lanchester from "The Bride of Frankenstein" (1935) also is in this film as Mrs. Oates, the family cook, who doesn't mind "a nip" or two of brandy after a long (or short) day in the kitchen. I have never seen a movie featuring an old dark house where Elsa Lanchester is on staff that would entice a sane person to a weekend visit.
Directed by Robert Siodmak, who also directed "The Killers"(1945), probably the best adaptation of an Ernest Hemingway short story on film, this movie may not be as bloody as post-1970's crop of modern thrillers, but I doubt anyone would be able to watch it alone in a dark house (or, worse, in an empty old theater!) around midnight and not get a serious case of the yips.
Dorothy McGuire--a undeservedly not well-remembered leading lady--gives a fine performance as the mute girl. She received only one Academy Award nomination in her career despite many good performances.