This film is an extremely entertaining psychological thriller with Carrol Baker excellent as a rich American widow getting away from it all at a secluded Italian villa. Enter smart aleck down on his luck playboy, Lou Castel, who has some golddigging motives behind his slick hipster seduction techniques and has no qualms about how he gets what he wants. He encourages Baker's character's incipient alcoholism and dubious self-esteem, brings in his supposed 'sister' to help drag Baker even further into a maze of sick mind games, drug addiction and group sex, all culminating in a descent into near-madness and self-destructive depravity.
I won't give away anymore, suffice to say that the film delivers on its swinging sixties, Euro sleaze ambience and psychological suspense thriller credentials in spades. Director Umberto Lenzi's work has been, at best, uneven and he's churned out his share of crap. However, he made some quite good giallos and crime pictures in the sixties and seventies and this is one of them (other good films by Lenzi -- SPASMO, SEVEN BLOODSTAINED ORCHIDS, ASSAULT WITH A DEADLY WEAPON, to name only a few).
Unfortunately this film is ofen confused with another okay but not-quite-as-good Lenzi film that was also released briefly here in America under the same PARANOIA title (but is more commonly known, especially on video, as A QUIET PLACE TO KILL).

Alessandro has a thing or two to learn. Carroll Baker, in her role, is the perfect teacher.

An alcoholic drifter spends Halloween in his hometown of Albany, New York after returning there for the first time in decades.

A reluctant cavalry Captain must track a defiant tribe of migrating Cheyenne.

A race-car driver who's down on her luck is invited by her ex-husband's wife to stay at their plush villa. The two women form a bond, and it's not long before their mutual dislike for the husband culminates into a plan to kill him. As it turns out, though, they're not alone in plotting murder.

The epic tale of the development of the American West from the 1830s through the Civil War to the end of the century, as seen through the eyes of one pioneer family.

丈夫性无能，妻子色情狂；佳偶成怨偶，虚度好时光；可怜妻娇艳，红杏要出墙；丈夫忆母病，女婿变情郎！

Hard-edged cop John Kimble gets more than he bargained for when he goes undercover as a kindergarten teacher to get the goods on a brutal drug lord while at the same time protecting the man's young son. Pitted against a class of boisterous moppets whose antics try his patience and test his mettle, Kimble may have met his match … in more ways than one.

A young rape victim tries desperately to pick up the pieces of her life, only to find herself at the mercy of a would-be rescuer.

1958 film by William Wyler

In honor of his birthday, San Francisco banker Nicholas Van Orton, a financial genius and a cold-hearted loner, receives an unusual present from his younger brother, Conrad: a gift certificate to play a unique kind of game. In nary a nanosecond, Nicholas finds himself consumed by a dangerous set of ever-changing rules, unable to distinguish where the charade ends and reality begins.