Intolerance of uncertainty, paranoia, and prodromal symptoms: Comparisons between a schizophrenia spectrum disorder, anxiety disorder and non-clinical sample.

Background: Greater Intolerance of Uncertainty (IU: the tendency to find uncertainty negative) is associated with greater paranoia (mistrust of others) in clinical samples with schizophrenia spectrum disorders (SSDs). Questions remain on whether the relationship between IU and paranoia/prodromal symptoms is: (1) specific over other related negative affective traits and cognitive biases, and (2) specific to SSDs or is transdiagnostic.

Methods: To examine these research questions, we conducted a survey in those with SSDs (n = 103), anxiety disorders (n = 102) a non-clinical sample (n = 102). Questionnaires included: IU, paranoia, prodromal symptoms of schizophrenia, neuroticism and jumping to conclusions bias.

Results: IU, neuroticism and jumping to conclusions bias were elevated in those with SSDs and anxiety disorders, compared to the non-clinical group. Both paranoia and prodromal symptoms were highest in those with SSDs, then anxiety disorders and lowest in the non-clinical group. Greater IU was associated with greater paranoia and prodromal symptoms across SSDs, anxiety disorders and a non-clinical sample. The majority of the relationships between IU and paranoia/prodromal symptoms remained significant when controlling for neuroticism and the jumping to conclusions bias. However, the relationship between IU and paranoia in the SSD group was not specific over the jumping to conclusions bias.

Discussion: These findings highlight the potentially transdiagnostic role of IU in paranoia/prodromal symptoms across SSDs and anxiety disorders, which has implications for the development of transdiagnostic treatment interventions for SSDs and anxiety disorders.