Is Hayley Mills a giallo queen? Let’s examine the evidence: She’s in the Agatha Christie movies Endless Night and Appointment with Death, as well as the Sidney Hayers psychological thriller Deadly Strangers. Heck, That Darn Cat! has a lot of elements of confused identity and mishearing critical evidence. You know, if The Parent Trap was slightly askew, you could see its tale of twins who never knew the other existed uniting to ruin relationships as an Italian thriller.

The jury is out on Ms. Mills being a giallo star — maybe if she’d made a voyage to Italy at some point — but Twisted Nerve really feels like it could fit into the post-Bava pre-Argento world of detective movies that were coming out of that country.

Martin Durnley (Hywel Bennett, who was also in Endless Night and The Family Way with Mills) is a rich young man with an invalid brother and a mother who has moved on to her new husband. So what else does he have to do than to become someone else, the mentally challenged Georgie, and start shoplifting toys and acting like a child? Especially if it gains the interest of Susan?

This movie pushes all the buttons, starting — instead of ending! — with a square up reel* that apologizes for suggesting that mentally retarded people are murderous. It then doubles down thanks to a scene where Martin sensually rubs his own chest while staring at a stack of male muscle magazines. And oh yeah — he’s obsessed with Susan enough to stage this charade yet when her neglected mother attempts to Mrs. Robinson him, he dispatches her with an axe. There’s also a shocking moment — for Susan — where Martin just casually disrobes in front of her and instead of her reacting with any arousal, she’s just confused and perhaps even upset as his alien nature makes seeing him in a sexual manner incredibly strange.

Yet even when he gets to touch her, it’s as if he can’t. Martin once had control over Georgie and thought it was all a ruse, but it looks like now he’s lost control.

I love that this movie has pretensions toward art. It quotes “Slaves” by George Sylvester Viereck — “No puppet master pulls the strings on high. Proportioning our parts, the tinsel and the paint. A twisted nerve, a ganglion gone awry predestinates the sinner and the saint.” — while also keeping one foot firmly in the world of exploitation. I mean, the tagline is “Cleaver. Cleaver. Chop. Chop. First the mom and then the pop. Then we’ll get the pretty girl. We’ll get her right between the curl.”

Even if you haven’t seen this movie, you may know its Bernard Herrmann score, which was whistled by Elle Driver as she attempted to kill The Bride in Kill Bill.

*”In view of the controversy already aroused, the producers of this film wish to re-emphasise what is already stated in the film, that there is no established scientific connection between mongolism and psychiatric or criminal behaviour.”