Self-Related Incompleteness in Obsessive-Compulsive Disorder

Summary Background: Incompleteness is increasingly discussed as a clinically relevant motivational dimension of obsessivecompulsive disorder (OCD). So far, research has focused on incompleteness in terms of ‘not just right experiences’ (NJREs), whereas self-related incompleteness, an OCD-specific variant of depersonalization, has hardly been investigated. The goal of this study is to develop an economical self-rating instrument to assess the severity of self-related incompleteness in OCD. Methods: 190 OCD patients received 24 items covering the contents of self-related incompleteness and a number of further measures to investigate construct validity. Results: On the basis of conceptual and statistical considerations, we developed a questionnaire for self-related incompleteness (‘Questionnaire on Self-Related Incompleteness», QSI-12) covering 4 dimensions of self-related incompleteness (depersonalization, derealization, robot-like self-experience, lack of lively feelings) with 3 items/ dimensions. A structural equation model shows a good fit of empirical data and model structure. The QSI-12 total scales’ and the subscales’ internal consistency is excellent. Self-related incompleteness and NJREs uniquely and independently contribute to the prediction of OCD symptom severity and show differential relationships to depersonalization/derealization and obsessive-compulsive personality traits. Thus, both phenomena represent clinically meaningful aspects of incompleteness in OCD which can be clearly differentiated from each other. Conclusion: The QSI-12 is a reliable and valid screening instrument to assess individual levels of self-related incompleteness in OCD.