A passionate sex scene with Derek and Sharon was written in the original script, but it was never filmed.
The character of Lisa suffers from a mental disorder known as erotomania.
According to the first draft of the script, the scene where Lisa seduces Derek in his car was originally supposed to be more sexually revealing than what was filmed.
The backless red dress Lisa wears to the hotel (and on the film's poster) was sewn from scratch, using design elements the actress playing her liked from different dresses considered for that sequence. The rest of the garments used in the film were store-bought.