Was made around 1985/1986. Starred her and Christian Slater. Shannon Doherty was in it as well.
"Highschool" drama where Ryder, who has been accepted as a fourth member of a group of three girls named "Heather"(Ryder's not named Heather). To make a long story short, her and Slater start killing the girls(and others) and making it look like suicides. Kind of quirky, sort of dark. There were a few other known stars in it, but I haven't seen it in years. If you are familiar with the movie "War Games", the guy who played "General Berringer" plays a memorable role of a father of a footbal star who kills himself(murdered) and framed to be gay, and proclaims at the funeral, "I love my dead gay son"(ok, you have to see it to see the humor).