A psychological thriller is a genre of fiction that focuses on the unstable or delusional psychological states of its characters. These stories often explore themes of manipulation, obsession, and the complexities of the human mind. The tension typically arises from the characters' internal struggles rather than external threats, creating a sense of unease and suspense. In psychological thrillers, the plot often involves twists and turns that challenge the reader's perception of reality. Characters may be unreliable narrators, leading to unexpected revelations. Popular examples of this genre include works by authors like Gillian Flynn and Patricia Highsmith, which delve into the darker aspects of human behavior and relationships.