Cross-sectional and longitudinal associations between temperament and delusional ideation

Delusional ideation (DI), a dimensional construct ranging from subclinical to clinical severity, refers to beliefs disconnected from reality and persistently held despite contradictory evidence. Worsening subclinical DI has predicted transition to psychosis; thus, identifying enduring risk factors for DI could facilitate targeted prevention. This study will examine which factors of temperament robustly predict DI cross-sectionally, then which further predict DI longitudinally, with aim to inform prevention and future research in delusion-prone individuals.

In a longitudinal study, a middle-aged adult community sample (n = 141) completed (1) the Adult Temperament Questionnaire measuring factors of Effortful Control, Negative Affect, Extraversion/Surgency, plus Orienting Sensitivity, and (2) the Peters Delusions Inventory 21-item assessing three DI dimensions, specifically Paranoia, Grandiosity, and Magical Thinking. Path models were employed for both cross-sectional and longitudinal analyses to examine how the four temperament factors at baseline simultaneously related to the three DI dimensions at the same timepoint, and then approximately one-year later.

Path models revealed Negative Affect had the strongest associations with DI overall. Cross-sectionally, higher Negative Affect was robustly related to higher Paranoia and to a lesser extent Magical Thinking; higher Extraversion/Surgency was associated with higher Grandiosity. Longitudinally, only Negative Affect was a significant predictor of DI, specifically for Paranoia.

Assessing temperament as predispositions through a comprehensive approach is crucial for advancing the understanding of individual predispositions associated with developing DI. Our findings suggest Negative Affect represents a core vulnerability to DI, especially Paranoia, which is critical to inform targeted prevention.