Psychosis as a disorder of the social brain. A different angle on social cognition and behaviour

Paranoia is a key feature of psychotic-spectrum disorders, such as schizophrenia. Though we might assume that psychosis only affects people with a diagnosed mental health condition, in fact, several healthy individuals also experience paranoid thoughts on a regular basis. Thus, everyone occurs somewhere on a spectrum, with most people experiencing very few paranoid thoughts, and around 10-15 % of the population experiencing them frequently. Here, I will present some of our new work which explores whether paranoia represents the dysfunction of an evolved social threat detection mechanism. The ability to detect and respond to social threats was likely favoured by evolution because of its beneficial effects in allowing us to forge alliances, and detect and avoid enemies in our complex and sometimes dangerous social worlds. Our research shows that everyone experiences increases in “live” paranoid thinking when faced with social threat – but that the threshold for detecting threat is lowered in people who are highly paranoid in their daily lives. I also describe how increases in paranoid thinking affects social cognition and behaviour in genuine social interactions.