Believing is seeing : The causal role of interpretive bias in anxiety

Over the past 20 years evidence has accumulated stating that anxiety is associated with a negative interpretive bias. That is, high anxious individuals have the tendency to interpret ambiguous information in a more threatening way than low anxious individuals. Cognitive theories argue that this biased information processing is not an incidental epiphenomenon of anxiety, but that it plays a critical role in the aetiology and maintenance of pathological anxiety. Thus, a causal relationship is predicted in which interpretive bias affects anxiety. Studies using a cross-sectional design revealed a relationship between interpretive bias and anxiety, yet, in such studies, the direction of that relationship remains unclear. To examine whether interpretive bias causes anxiety, experiments with a pure experimental design are indispensable. Therefore, the aim of the present thesis was to examine the prediction that interpretive bias contributes to anxiety. Examination of the causal nature is not only of theoretical relevance, but also of clinical importance. Together with depression, anxiety disorders are the most common psychiatric disorders. Also, anxiety disorders result in the second greatest reduction in quality of life (immediately following coronary heart disease). A better understanding of the development and maintenance of such anxiety disorders is important and research on the causal relationship between interpretive bias and anxiety could shed light on this issue. Different experimental studies were conducted to elucidate the causal relationship between interpretive bias and anxiety and the main conclusion that can be drawn from these studies is that the results support the hypothesis that interpretive bias can play a causal role in anxiety. First of all, it proved possible to reliably modify interpretations. Secondly, while it seems that the effects on anxiety are more fragile, across different studies in different laboratories the weight of evidence suggests that interpretive bias affects anxiety. Thus, results are consistent with a causal relationship between interpretive bias and anxiety. Note that the results regarding the clinical potential of interpretive bias retraining are suggestive rather than conclusive, leaving interpretations of the potential therapeutic merits of the training method open for future research.