This came out in 1980, in the 'second wave' of American slasher films, along with Friday the 13th, Prom Night, Terror Train, etc. Silent Scream stars Rebecca Balding (damn cute in this one, eyecandylicious) who was on the tv sitcom Soap I believe. And she does a pretty decent acting job here as well.
The movie is worth a watch for the really pretty interesting backstory of the Engels family, but is otherwise cliche-ridden, with empty-brained college students, cheesy music (some of it outright stolen from Psycho) and lame sexploits with poor dialogue. There is nothing artistically stand-out about this one, but it's one saving grace is the storyline about Victoria Engels (played rather well by Barbara Steele) and her 'brother' and mother. The movie is set on the Calfornia coast in a creepy mansion (a boarding house for college students).
There are a few good and predictable scares, and a sinister secret passage way and room in the mansion that works well. The homicide investigation subplot is dumb and rather shoddily thrown in to break the tension. The two cops are boring and useless. The main and only highlight is Barbara Steele's character, and I'll only say this if you decide to watch it (it's on Netflix instant play): she never utters a word.
Not the best, and certainly not the worst, slasher film ever made.