Paranoia as a continuum in the population

Paranoid beliefs, though key to the diagnosis of paranoid schizophrenia, are not exclusively seen in patients suffering from this psychopathology and exist in less severe forms across different populations. Evaluating these symptoms as a continuum may be more interesting for the understanding of paranoia rather than the dichotomous approach to this kind of ideation. The main goal of the current research is to assess how paranoid beliefs are present across different populations. Using the Portuguese versions of the General Paranoia Scale and the Paranoia checklist, we compared the endorsement of paranoid beliefs in 187 subjects (64 healthy controls from the general population, 32 relatives from schizophrenia patients, 30 patients in remission and 61 patients with acute schizophrenia symptoms). The results show that paranoia is present throughout the population, from non-clinical forms to more severe clinical samples, demonstrating a continuum of increased frequency and intensity until it reaches a delusional level. Environmental factors in the endorsement of such beliefs are also discussed