Background: Worry processes are implicated in paranoia and anxiety. However, clinical studies focused on patients with co-occurring paranoia and anxiety. As both paranoia and anxiety are distributed across clinical and non-clinical groups, an investigation on worry processes among non-clinical individuals will allow us to delineate the specific worry mechanisms in paranoia and anxiety respectively. 

Aims: To identify clusters of non-clinical individuals who report varied levels of paranoia and anxiety, and to compare worry processes across clusters. 

Method: An online survey, consisting of self-report questionnaires on generalized anxiety, paranoia, and worry processes, was completed by 2796 undergraduate students. A multiple-step validity check procedure resulted in a subsample of 2291 students, upon which cluster analyses and multivariate analyses of variance were conducted. 

Results: Four clusters of individuals were identified: (1) high paranoia/moderate anxiety, (2) average paranoia/high anxiety, (3) average paranoia/average anxiety, and (4) low paranoia/low anxiety. A unique cluster of individuals with high paranoia but low/average level of anxiety was not found. Cluster 1 reported a significantly higher intensity of day-to-day worries, a higher level of meta-worry, and more extreme meta-cognitive beliefs about worry than other clusters. 

Conclusions: Individuals with high paranoia tended to report anxiety as well, but not vice versa. Our findings supported a hierarchical structure of anxiety and paranoia. All worry processes were exacerbated in individuals with paranoia and anxiety than those with anxiety alone. (c) 2018 Elsevier B.V. All rights reserved.