Cognitive behavioral therapy, consisting of exposure and response prevention and cognitive restructuring, is still one of the most effective treatments for obsessive compulsive disorder. However, some patients do not fully benefit from the treatment. This condition results in more search for novel approaches that can contribute to effectiveness of standard treatments. In this regard, the use of technology-based methods in recent researches is noteworthy. Cognitive bias modification (CBM) is one of these current efforts of technology-based methods. CBM involves computerized tasks designed to modify some cognitive biases such as attention and interpretation associated with psychopathology, particularly anxiety disorders. Researches have generally demonstrated that cognitive bias modification can be effective way to alter cognitive biases and to reduce anxiety symptoms. In recent years, there have been also some studies to investigate the potential effects of cognitive bias modification for obsessive compulsive disorder.The results of both CBM-Interpretation (CBM-I) and CBM-Attention (CBM-A) studies have shown that it is an effective and promising method in reducing cognitive biases in obsessive compulsive disorder (OCD). Although these studies are highly informative, they do not provide information about the causal role one bias has during the operation of another. In recent years, there has been a growing consensus that both biases arise from the same system, thereby, it is possible that modifying the system to alter one bias (e.g., attention), will also impact on the presence of the other bias.). In line with this notion, there are a couple of studies to test the effect of Combined Cognitive Bias Modification (CBM-C) which is combination of both CBM-A and CBM-I in intervention programs. The results of these studies are generally very positive. Although it is well established that attention bias and interpretation bias each have a key role in the development and maintenance of OCD, only one bias is targeted in CBM studies of OCD. Considering that a combined cognitive bias may contribute to the maintenance of several disorders, in order to try to maximise the potential clinical impact, the present research aims at exploring whether the combination of the CBM-A and CBM-I procedures would be more effective in reducing cognitive biases and OC symptoms than either alone. It is expected that internet-delivered CBM-C (iCBM-C) will result in superior treatment outcomes as indexed by internet-delivered CBM-I intervention only (iCBM-I), internet-delivered CBM-A intervention only (iCBM-A), and wait-list control (WLC).
A factorial randomised controlled trial comparing internet-delivered combined cognitive bias modification intervention (iCBM-C) versus internet-delivered CBM-interpretation intervention (iCBM-I), internet-delivered CBM-attention intervention (iCBM-A) and wait-list control on obsessive-compulsive (OC) symptoms, OC-beliefs, OC-related interpretation and attention biases