Dysfunctional beliefs in the process of change of cognitive treatment in obsessive compulsive checkers.

Cognitive behaviour therapy (CBT) is considered to be effective in the reduction of obsessive compulsive symptoms. However, questions remain as to how CBT works. Cognitive-behavioural models postulate that negative appraisals of intrusive thoughts and dysfunctional beliefs that give rise to them underlie the development and maintenance of obsessive-compulsive disorder (OCD). The current study aimed to study this hypothesis by investigating the processes of change over the course of cognitive treatment for OCD. Furthermore, a new theoretical approach and method for studying processes of change was presented. The participants were seven patients suffering from OCD with predominantly checking symptoms. Process variables (beliefs, anxiety and compulsions) were measured using idiosyncratic diaries and were analysed on an intra- and inter-individual level using dynamic systems methods. Results showed significant decreases in credibility of dysfunctional beliefs in six out of the seven participants, which is in line with the cognitive-behavioural model. Associations between process variables were in general medium to high. However, the actual patterns of change showed important intra- and interpersonal differences. Results indicated that different paths can lead to clinical recovery, and it was concluded that process studies that focus on individual trajectories of change can contribute to our understanding of OCD and its treatment. Furthermore, dynamic systems methods provide insight into intra-individual processes and shed a new light on variability.

Symptom dimensions in OCD: item-level factor analysis and heritability estimates.

To reduce the phenotypic heterogeneity of obsessive-compulsive disorder (OCD) for genetic, clinical and translational studies, numerous factor analyses of the Yale-Brown Obsessive Compulsive Scale checklist (YBOCS-CL) have been conducted. Results of these analyses have been inconsistent, likely as a consequence of small sample sizes and variable methodologies. Furthermore, data concerning the heritability of the factors are limited. Item and category-level factor analyses of YBOCS-CL items from 1224 OCD subjects were followed by heritability analyses in 52 OCD-affected multigenerational families. Item-level analyses indicated that a five factor model: (1) taboo, (2) contamination/cleaning, (3) doubts, (4) superstitions/rituals, and (5) symmetry/hoarding provided the best fit, followed by a one-factor solution. All 5 factors as well as the one-factor solution were found to be heritable. Bivariate analyses indicated that the taboo and doubts factor, and the contamination and symmetry/hoarding factor share genetic influences. Contamination and symmetry/hoarding show shared genetic variance with symptom severity. Nearly all factors showed shared environmental variance with each other and with symptom severity. These results support the utility of both OCD diagnosis and symptom dimensions in genetic research and clinical contexts. Both shared and unique genetic influences underlie susceptibility to OCD and its symptom dimensions.

Processes of change in cognitive-behavioural treatment of obsessive-compulsive disorder: Current status and some future directions.

The present paper discusses theoretical and methodological issues involved in the processes of change in cognitive-behavioural treatment (CBT) of obsessive-compulsive disorder (OCD). Treatment outcome studies showed that CBT is effective in reducing obsessive-compulsive symptoms. However, why and how CBT works cannot be corroborated by comparing pre- and post-assessment. Recently, there has been a resurgence of interest in theory driven process studies. By showing patterns of change over time, process studies can contribute to our insight into the actual mechanisms of change during treatment. We review process research in the field of OCD and discuss methodological issues involved in process studies for this particular disorder. It is concluded that studying the processes of change harbours promising possibilities for bridging the gap between theory and clinical practice.

The role of the COMT Val(158)Met polymorphism in the phenotypic expression of obsessive-compulsive disorder.

Obsessive-Compulsive Disorder (OCD) is characterized by the presence of obsessions and compulsions, and shows considerable phenotypic variability. Family and twin studies have indicated a genetic component in the etiology of OCD, and the catechol-O-methyl transferase (COMT) gene is an important candidate gene for OCD. This study investigates the influence of the functional COMT Val158Met polymorphism on the phenotypic expression of OCD, using an item-level factor-analytic approach in a large sample. The COMT Val158Met variant was genotyped in 373 patients and 462 controls. It was tested whether there was an association between the COMT Val158Met polymorphism and OCD or dimensional phenotypes such as YBOCS severity score, age of onset of obsessive-compulsive symptoms and six symptom dimensions recently found in a large item-level factor-analytic study [Katerberg et al., submitted]. We further investigated possible sex-specific associations between the COMT Val158Met polymorphism and OCD or dimensional phenotypes. There was a trend for an association of the COMT 158Met allele with OCD in males, and an interaction between the COMT Val158Met genotype and sex on the somatic and sensory phenomena symptom dimension, with females showing lower scores. In conclusion, a dimensional approach seems fruitful in detecting genes of importance for OCD.

The role of the brain-derived neurotrophic factor (BDNF) val66met variant in the phenotypic expression of obsessive-compulsive disorder (OCD).

Evidence suggests that the Val66Met variant of the brain-derived neurotrophic factor (BDNF) gene may play a role in the etiology of Obsessive-Compulsive Disorder (OCD). In this study, the role of the BDNF Val66Met variant in the etiology and the phenotypic expression of OCD is investigated. Associations between the BDNF Val66Met variant and OCD, obsessive-compulsive symptom dimensions, Yale-Brown Obsessive Compulsive Scale (YBOCS) severity scores, age of onset and family history of obsessive-compulsive symptoms were assessed. The BDNF Val66Met variant was genotyped in 419 patients with sub-/clinical OCD and 650 controls. No differences in allele or genotype frequency were observed between cases and controls. In females with OCD, the Met66Met genotype was associated with later age of onset and a trend for a negative family history, whereas the Val66Val genotype was associated with a trend for lower YBOCS severity scores. Item-level factor analysis revealed six factors: 1) Contamination/cleaning; 2) Aggressive obsessions/checking; 3) Symmetry obsessions, counting, ordering and repeating; 4) Sexual/religious obsessions; 5) Hoarding and 6) Somatic obsessions/checking. A trend was found for a positive association between Factor 4 (Sexual/religious obsessions) and the BDNF Val66Val genotype. The results suggest that BDNF function may be implicated in the mediation of OCD. We found that for the BDNF Met66Met genotype may be associated with a milder phenotype in females and a possible role for the BDNF Val66Val genotype and the BDNF Val66 allele in the sexual/religious obsessions.