a b s t r a c t a r t i c l e i n f oIn the past decade there has been an increasing interest in the levels of obsessive-compulsive symptoms (OCS) found in patients with schizophrenia or related disorders. The widely acknowledged gold standard measure of the severity of OCS is the content-free version of the Yale-Brown Obsessive-Compulsive Scale (Y-BOCS) (Goodman et al., 1989a,b). However, factor analytic research in patients with obsessive-compulsive disorder (OCD) provided varied results. So far no study has been conducted on the factor structure of the Y-BOCS in patients with schizophrenia. The present study addresses this issue. We administered the Y-BOCS in a sample of 217 patients with schizophrenia or related disorders and comorbid OCS who participated in a multicentre cohort study. We used principal component analysis (PCA) to explore the underlying factor structure. A two-factor solution consistent with the originally proposed scoring structure of the Y-BOCS provided the optimal fit. We also found some support for a three-factor solution consistent with earlier findings by Kim et al. and Moritz et al. (Kim et al., 1994;Moritz et al., 2002). The produced factors showed good reliability and strong correlations with the Y-BOCS Total score. However, the resistance to compulsion item failed to demonstrate adequate correlation to the Total score, a finding consistent with earlier findings in several studies with patients with OCD.

The proneness-persistence-impairment (PPI) model states that psychotic experiences are more likely to lead to impairment if their expression becomes persistent. Higher genetic risk for psychosis is known to affect proneness and persistence of subclinical positive symptoms. Less is known about potential effects of genetic risk on the course of subclinical negative symptoms, impairment, and their subsequent associations. The current study examined these issues in a large sample (n=1131), consisting of individuals with higher genetic risk (siblings of patients with psychotic disorders, n=703) and lower genetic risk (controls without a family member with lifetime psychosis, n=428). Psychotic experiences were assessed with the CAPE questionnaire, at two time points three years apart. Participants were allocated to one of four groups representing developmental course: stable low, decreasing, increasing or persisting subclinical positive/negative symptoms. Lifetime clinical psychosis was an exclusion criterion at baseline. Higher genetic risk status was found to be associated with a persisting course of both subclinical positive and negative symptoms, symptom-related distress and functional impairment. There is no evidence for an effect of genetic risk status on the association between developmental course and impairment. The results of the current study underline the importance of assessing psychotic experiences in the context of genetic risk, multidimensional and over time. Additionally, the current findings both underscore and contribute to the PPI model: psychotic experiences are more likely to lead to impairment if their expression becomes persistent, both in individuals with higher and lower genetic risk for psychosis.

Introduction: Recent life events are associated with transition to and outcome in psychosis. Childhood trauma and personality characteristics play a role in proneness to adult life events. However, little is known about the relative contribution and interrelatedness of these characteristics in psychotic disorders. Therefore, we investigated whether Five-Factor Model (FFM) personality traits and childhood trauma (abuse and neglect) predict adult life events, and whether the effect of childhood trauma on life events is mediated by personality traits. Method: One hundred and sixty-three patients with psychotic disorders were assessed at baseline on history of childhood maltreatment and FFM personality traits, and on recent life events at 3-year follow-up. Results: Childhood abuse is associated with negative life events, and part of the effect of childhood abuse on negative life events is mediated by openness to experience. Openness to experience and extraversion are associated with more positive and negative life events. Childhood neglect and lower extraversion are related to experiencing less positive events. Conclusion: The association between childhood trauma and recent life events is partly mediated by personality. Future research could focus on mechanisms leading to positive life events, as positive life events may buffer against development of mental health problems.

Cross-classified multilevel models improved standard error estimates of covariates in clinical outcomes -a simulation study,