Abstract
According to the cognitive behavioral model of severe health anxiety (hypochondriasis) four central maintaining mechanisms are how the individual perceives the risk of disease and how negative its consequences would be, attention to bodily sensations, and intolerance of uncertainty. The aim of the present study was to investigate the mediating role of these putative mechanisms in Internet-delivered CBT for severe health anxiety. We analyzed data from an RCT where participants were randomized to Internet-delivered CBT (n=40) or to a control condition (n=41). Mediators and outcome, i.e. health anxiety, were assessed weekly throughout the treatment, enabling fulfillment of the criterion of temporal precedence of changes occurring in the mediator in relation to the outcome to be met. The results showed that reduced perceived risk of disease, less attention to bodily symptoms, and reduced intolerance of uncertainty significantly mediated improvement in health anxiety. The study supports the validity of the cognitive behavioral model of health anxiety. The findings have theoretical and clinical implications as they indicate processes that may be causally related to the improvements observed after CBT for health anxiety.