The Validity of the 16-Item Version of the Prodromal Questionnaire (PQ-16) to Screen for Ultra High Risk of Developing Psychosis in the General Help-Seeking Population

In order to bring about implementation of routine screening for psychosis risk, a brief version of the Prodromal Questionnaire (PQ; Loewy et al., 2005) was developed and tested in a general help-seeking population. We assessed a consecutive patient sample of 3533 young adults who were help-seeking for nonpsychotic disorders at the secondary mental health services in the Hague with the PQ. We performed logistic regression analyses and CHi-squared Automatic Interaction Detector decision tree analysis to shorten the original 92 items. Receiver operating characteristic curves were used to examine the psychometric properties of the PQ-16. In the general help-seeking population, a cutoff score of 6 or more positively answered items on the 16-item version of the PQ produced correct classification of Comprehensive Assessment of At-Risk Mental State (Yung et al., 2005) psychosis risk/clinical psychosis in 44% of the cases, distinguishing Comprehensive Assessment of At-Risk Mental States (CAARMS) diagnosis from no CAARMS diagnosis with high sensitivity (87%) and specificity (87%). These results were comparable to the PQ-92. The PQ-16 is a good self-report screen for use in secondary mental health care services to select subjects for interviewing for psychosis risk. The low number of items makes it quite appropriate for screening large help-seeking populations, thus enhancing the feasibility of detection and treatment of ultra high-risk patients in routine mental health services. © The Author 2012

An intervention study to prevent relapse in patients with schizophrenia

Purpose: To determine whether the use of relapse prevention plans (RPPs) in nursing practice is an effective intervention in reducing relapse rates among patients with schizophrenia. Design and Methods: Experimental design. Patients with schizophrenia (or a related psychotic disorder) and nurses from three mental health organizations were randomly assigned to either an experimental (RPP) or control condition (care as usual). The primary outcome measure was the psychotic relapses in the research groups. Results: The relapse rates in the experimental and control groups after 1-year follow-up were 12.5% and 26.2%, respectively (p=.12, ns). The relative risk of a relapse in the experimental versus the control group was 0.48(ns). Conclusions: In this study no statistically significant effects of the intervention were found. Effectiveness research in this area should be continued with larger sample sizes and longer follow-up periods

Improving Genetic Prediction by Leveraging Genetic Correlations Among Human Diseases and Traits

Genomic prediction has the potential to contribute to precision medicine. However, to date, the utility of such predictors is limited due to low accuracy for most traits. Here theory and simulation study are used to demonstrate that widespread pleiotropy among phenotypes can be utilised to improve genomic risk prediction. We show how a genetic predictor can be created as a weighted index that combines published genome-wide association study (GWAS) summary statistics across many different traits. We apply this framework to predict risk of schizophrenia and bipolar disorder in the Psychiatric Genomics consortium data, finding substantial heterogeneity in prediction accuracy increases across cohorts. For six additional phenotypes in the UK Biobank data, we find increases in prediction accuracy ranging from 0.7 for height to 47 for type 2 diabetes, when using a multi-trait predictor that combines published summary statistics from multiple traits, as compared to a predictor based only on one trait. © 2018 The Author(s)

A quantitative measure for expressed emotion

The items of the Five Minute Speech Sample, an instrument to elicit relatives' expressed emotion, were investigated in a follow-up study of 120 parents of adolescents with recent-onset schizophrenia. A composite scale was constructed using Mokken scale analysis. From the 9 available items, 6 formed a unidimensional and cumulative scale. This scale was applicable for the total parent group, as well as for fathers and mothers separately. A second scale of 2 items did not meet the criteria for the Mokken model completely and was applicable for the parent group as a whole, but not for fathers and mothers as separate groups. The configuration of the subscales as found with the Mokken scale analysis was comparable with the results of principal component analysis. A quantitative measure may detect smaller differences in expressed emotion than the dichotomous index and expands the possibilities for statistical test

The P3 event-related potential in young recent-onset schizophrenic patients

In schizophrenic patients, the amplitude of the P3 event-related potential (ERP) is usually decreased and the latency is often prolonged. Most ERP studies have compared schizophrenic patients with chronic illness or in mixed age groups with age-matched control subjects. However, P3 latency and amplitude change with age, and P3 latency increases more rapidly in schizophrenic patients than in control subjects. To investigate whether mixed age groups and chronic illness have been determining factors in ERP results, P3 was measured in 15 young patients (mean age 21.6 years) with recent-onset schizophrenia and compared with age-matched controls. P3 amplitudes were decreased in the schizophrenic group compared with the control group. P3 latencies were less significantly prolonged in the schizophrenic group than in other studies. Furthermore, in an exploratory study, the ERPs resulting from application of the irrelevant tones in some schizophrenic patients demonstrated ERP activity at latencies of 250-600 ms, while little or no activity was present at these latencies in control subjects. It is hypothesized that a defect in inhibition of incoming sensory information in the nucleus reticularis thalami may play a role in the pathogenesis of schizophrenia. Such a defect could result in a dysfunctional filter function of external stimuli and may therefore affect the social and psychological functioning of the patient. (C) 1998 Rapid Science Lt