When this episode first aired, the alien was deemed too frightening to show by several ABC affiliates. They instead showed a black screen whenever the alien appeared and showed footage of the alien later during the evening news.
This was the last episode to include the extended intro sequence.
The brief shot of Allen Leighton midway through his transition into an alien creature was devised by actor Robert Culp and makeup artist Fred B. Phillips, and was filmed without the knowledge or participation of director Byron Haskin.
When Allen has his first psychotic breakdown, he calls himself Caliban. In William Shakespeare's "The Tempest," Caliban is the son of an evil witch and what might have been a demon. He is possibly demented, certainly dangerous, and the only entity on Prospero's island not gifted with human shape.
While writing the graphic novel Watchmen in the early 1980s, it was brought to author Alan Moore's attention that the final act of the novel broadly resembled the plot of The Architects of Fear. Moore worked this odd trivia into one of the novel's final scenes by having Sally Jupiter watching The Outer Limits on her TV.