Contributions of Worry and Social Anxiety to Paranoia in Clinical and Non-Clinical Samples: Cross-sectional and Longitudinal Results.

OBJECTIVES:Theoretical models implicate social anxiety and worry as potential drivers of paranoia; however, it is unknown which aspect of anxiety relates more strongly to paranoia, whether these relationships differ in clinical versus non-clinical populations and how these variables relate to one another over time. METHODS:143 schizophrenia spectrum disorder (SSD) and 89 non-clinical comparison (NCC) participants completed assessments of worry (Dunn Worry Questionnaire), social anxiety (Liebowitz Social Anxiety Scale) and paranoia (Revised-Green Paranoid Thoughts Scale). A subset (72 SSDs; 66 NCCs) completed longitudinal assessments over 6 months. Hierarchical regression was used to analyze the relative contribution of worry and social anxiety on paranoia severity within each group, for cross-sectional and longitudinal analyses. RESULTS:Worry, social anxiety, and paranoia were significantly elevated in SSD and intercorrelated. In NCCs, social anxiety accounted for more variance in paranoia than worry (16% vs. 3% in R2-change), but in SSDs, worry accounted for more variance in paranoia than social anxiety (14% vs. 5% R2-change). Longitudinal associations followed a similar pattern. In NCCs, change in social anxiety explained more variance than change in worry (18.5% vs. 6%), and in SSDs, change in worry explained more variance than change in social anxiety (26.5% vs. 0.5%), with social anxiety not adding meaningful variance to paranoia severity, above and beyond worry. DISCUSSION:Social anxiety and worry are both highly relevant for paranoia. In sub-clinical samples, paranoia may be more related to social anxiety, whereas worry may relate more to paranoia in clinical samples. These findings can inform intervention.