The article explores the changing meanings of psychological themes in the 1940s. In the early 1940s, these themes were largely disparaged by film critics and associated with horror but, by the late 1940s, psychological themes became highly valued through their association with realism. However, while this process increasingly distinguished the realist thriller from horror, the latter becoming largely associated with Gothic fantasy, critics also became disenchanted with the supposedly ‘realist’ thrillers of the late 1940s. If realism was valued in the extent to which it was part of an analysis of social problems, and offered a form of constructive social criticism, film critics increasingly came to see the realism of many Hollywood thrillers as merely stylistic or aesthetic. Ironically, the one feature that they continued to celebrate were the psychologically disturbed killers featured in many of these films, killers that were the point of continuity with the 1940s horror cycle of the early to mid-1940s.