The code-name for the character of 'The Sender' (Zeljko Ivanek) was John Doe #83. He is never known by any personal name in the picture.
The film's director Roger Christian has said of this movie in an interview: ''This was the beginning of my career as a director, and it was a real battle with the producer and the studios who were dumping it. They were hiding it and I was fighting...It came off the back of, first, Black Angel (1980) in particular got me a Hollywood agent, and a very good one, different from most of them. I was more interested in pursuing [Andrei] Tarkovsky [Andrei Tarkovsky]'s kind of way of filmmaking where I was making the film for the subconscious rather the conscious. I thought I'd better do something else, so I made The Dollar Bottom (1981)...That won the Academy Award, so that got me The Sender, and it was with Fox, 20th Century Fox, and then right when we were well into it, almost into production, they turned around and cancelled, and Paramount Pictures picked it up in three days, and we went straight ahead. But it's one of these films, I found out, as I said, Paramount were completely not interested in it, they really did nothing with it at the time, which was a shame... it was a very, very good script, and I got a really good cast of actors to do it, and it was a baptism by fire for me, with the producer and the studios and everything...''.
Screenwriter Thomas Baum based this horror movie's screenplay on his own real life experiences of growing up with a mother who was overly-protective and suffered from agoraphobia.
The favorite horror movie of director Quentin Tarantino for the year 1982 according to his audio-commentary for Hot Fuzz (2007). According to 'Tysto', ''he created his own video version from the R-rated and TV versions''.