Nearly every single person involved with the film were locals from the Portland, Oregon area.
The film was banned in the UK as part of the "Video Nasties" controversy in 1983 due to its so-called "graphic violence" and nudity, and was pulled off shelves nationwide. It was later given an uncut DVD release in 2004.
The film had already received notoriety in the UK after being featured on the BBC News as part of a report concerning the availability of uncertified video films. Even though the film had received a cinema certificate by the BBFC this led to it being banned and included on the DPP list of 72 video nasties. The film was eventually passed uncut in the UK in 2005.
The car the girls are driving appears to be a white early 80's Soviet made 4 door Lada Signet, a car that was never imported into the U.S. but was imported heavily in Canada. The majority of vehicles that appear in Unhinged happen to be either white, or whitish light colored vehicles - Perhaps a trend in Portland at the time, or just coincidence.
Released on VHS by CBS/Fox video in Australia and New Zealand in 1984.