Likewise, focusing clinical work on appraisals specifically, could be an important future direction to take due to this seeming to be a theme across the studies that this paper reviewed. Studies have found that an adapted CBT focusing on directly addressing mental contamination was more effective for some participants (Coughtrey, Shafran & Lee, 2013) and that appraisals played a key role in this. This therefore highlights the importance of investigating the role of appraisals further as research is beginning to demonstrate that they seem to have a significant impact upon mental contamination, which could have important clinical implications. Conclusions This synthesis has systematically and critically evaluated the research to date in the field of mental contamination. It has found that the majority of the research has focused, in some part, on adding to the evidence base that mental contamination is a separate construct from contact contamination. Now that a consensus has been reached on this point, the field has begun to move in different directions in an aim to further explore and understand the construct. Whilst this is promising in terms of widening the knowledge base, it has led to a confusing picture in the literature as there is less reliability between studies because of the lack of replication of findings. This therefore means that it is difficult to make any clear assertions about the relationship between mental contamination and psychological distress in a more specific manner. There does however, seem to be some promising findings emerging from the research into mental contamination and morality and associated negative emotions (such as shame and guilt). Whilst the research in this area remains in its infancy, replicable results across studies are being found, therefore warranting further investigation. Research in this area also has potential important clinical implications for the treatment of patients presenting with OCD as understanding how these associated negative emotions interact with mental contamination could help to identify specific vulnerabilities to the construct in the
Likewise, focusing clinical work on appraisals specifically, could be an important future direction to take due to this seeming to be a theme across the studies that this paper reviewed. Studies have found that an adapted CBT focusing on directly addressing mental contamination was more effective for some participants (Coughtrey, Shafran & Lee, 2013) and that appraisals played a key role in this. This therefore highlights the importance of investigating the role of appraisals further as research is beginning to demonstrate that they seem to have a significant impact upon mental contamination, which could have important clinical implications. Conclusions This synthesis has systematically and critically evaluated the research to date in the field of mental contamination. It has found that the majority of the research has focused, in some part, on adding to the evidence base that mental contamination is a separate construct from contact contamination. Now that a consensus has been reached on this point, the field has begun to move in different directions in an aim to further explore and understand the construct. Whilst this is promising in terms of widening the knowledge base, it has led to a confusing picture in the literature as there is less reliability between studies because of the lack of replication of findings. This therefore means that it is difficult to make any clear assertions about the relationship between mental contamination and psychological distress in a more specific manner. There does however, seem to be some promising findings emerging from the research into mental contamination and morality and associated negative emotions (such as shame and guilt). Whilst the research in this area remains in its infancy, replicable results across studies are being found, therefore warranting further investigation. Research in this area also has potential important clinical implications for the treatment of patients presenting with OCD as understanding how these associated negative emotions interact with mental contamination could help to identify specific vulnerabilities to the construct in the