Background: The COVID-19 pandemic brought about great uncertainty and significant changes in our people's everyday lives. In times of such crises, it is natural to seek explanations to overcome our fears and uncertainties, contributing to an increase to believe in conspiracy theories which, by yielding explanations, decrease uncertainty and ambiguity and may thus have an effect on mental well-being. In spite of this, the majority of research on conspiracy theories focused on their social effects with little attention to psychological effects. Thus, the aim of our present study was to examine the association between belief in conspiracy theories and different aspects of mental health during the COVID-19 pandemic in a general population sample. Methods: Our analyses included data from the Hungarian leg of the COMET-G (COVID-19 MEntal health international for the General population) study. The Hungarian sample included participants who completed a detailed questionnaire assessing belief in seven conspiracy theory items, as well as STAI-S and CES-D to measure state anxiety and depression, respectively, and answered questions related to their change in depression, anxiety and suicidal thoughts during the pandemic. Association between the individual beliefs as well as a composite Conspiracy Theory Belief Score (CTBS) and mental health measures was analysed using linear regression models. Results: Overall, belief in conspiracy theories was relatively moderate in our sample. Sex and age appeared to have a significant effect on the Overall Conspiracy Theory Belief Score (CTBS), with women having a higher score and scores increasing with age. Some of the individual beliefs also showed associations with age and sex. State anxiety and depression was not significantly associated with CTBS, however in case of depression some individual items were, and symptom clusters within CES-D also showed a pattern of association with some of the individual items. As far as changes in mental health during the pandemic is concerned, no association between overall beliefs and changes in anxiety or depression was found. However, higher overall belief in conspiracy theories was associated with a decrease in suicidal thoughts. Discussion: In our study, we explored the association between conspiracy theories and mental well-being as well as its changes during the COVID-19 pandemic. We found a specific pattern of association between belief in distinct theories and some aspects of depression, as well as lower increase in suicidal ideation in association with increased belief in conspiracy theories. Understanding the role of belief in theories can be key to designing mental health interventions when reacting to unforeseen events in the future. (Neuropsychopharmacol Hung 2022; 24(1): 42-55).
Keywords: COVID-19; anxiety; conspiracy theories; depression; mental health; mental health change; suicidal thoughts; suicide.