Do stress, depression and anxiety lead to beliefs in conspiracy theories over time? : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Clinical Psychology at Massey University, Albany, New Zealand

Abstract

Prior research has found positive correlations between various indicators of psychological distress such as anxiety, depression and stress, and belief in conspiracy theories. However, whether these relationships reflect causal effects remains unclear. In this preregistered longitudinal study, we tested whether anxiety, depression, and stress affect – and are affected by – belief in unwarranted conspiracy theories. Participants (N = 970) from Australia, New Zealand, and the United Kingdom completed seven monthly online surveys between October 2022 and March 2023. Using a multiple indicator random intercept cross-lagged panel model (RI-CLPM), we found support for only one of 15 preregistered hypotheses: a small within-person cross-lagged effect of anxiety increasing belief in conspiracy theories. Conversely, we found no evidence that belief in conspiracy theories increases psychological distress over time. These findings align with other longitudinal studies, suggesting that any reciprocal relationship between psychological distress and conspiracy beliefs is relatively small. This raises questions about the role of distress and existential threat as primary contributors to belief in conspiracy theories.