The lurid title could easily side-track you from what is essentially an extremely frightening exploration of a woman's descent into madness. You can read it, of course, in a material sense as the title suggests; but everything in this film has the potential to signify something else entirely, and its this ambiguity that makes this film so macarbe and interesting. IMDB reference : http://www.imdb.com/title/tt0067341/
You can stream Let's Scare Jessica to Death (1971) free and legally on OldReel, via the Internet Archive.
Yes — it is in the public domain and can be watched and shared freely.