Psychological thriller is a fictional thriller story which emphasizes the psychology of its characters and their unstable emotional states. In terms of classification, the category is a sub-genre of the broader ranging thriller category, with similarities to Gothic and detective fiction in the sense of sometimes having a "dissolving sense of reality", moral ambiguity, and complex and tortured relationships between obsessive and pathological characters. Psychological thrillers often incorporate elements of mystery, drama, and horror, particularly psychological horror.