A growing number of studies demonstrate high rates of subthreshold psychotic experiences, but there is considerable heterogeneity in rates due to study cohort and design factors, obscuring how prevalent psychotic experiences may or may not relate to rare psychotic disorders. In a representative general population sample (n = 4011) in Izmir, Turkey, the full spectrum of expression of psychosis was categorized across 5 groups representing (1) absence of psychosis, (2) subclinical psychotic experiences, (3) low-impact psychotic symptoms, (4) high-impact psychotic symptoms, and (5) full-blown clinical psychotic disorder and analyzed for continuity and discontinuity in relation to (1) other symptom dimensions associated with psychotic disorder and (2) proxies of genetic and nongenetic etiology. Results were tested for linear and extralinear contrasts between clinical and nonclinical and between disorder and nondisorder expression of psychosis. Demographic variables, indexing premorbid social adjustment and socioeconomic status, impacted mostly linearly; proxy variables of genetic loading (more or more severely affected relatives) impacted in a positive extralinear fashion; environmental risk factors sometimes impacted linearly (urbanicity and childhood adversity) and sometimes extralinearly (cannabis), occasioning a disproportional shift in risk at the clinical disorder end of the spectrum. Affective symptoms were associated with a disproportionally higher risk below the disorder threshold, whereas a disproportionally higher risk above the threshold was associated with psychotic symptom load, negative symptoms, disorganization, and visible signs of mental illness. Liability associated with respectively affective and nonaffective symptom domains, in interaction with environmental risks, may operate by impacting differentially over a quasi-continuous extended psychosis phenotype in the population.

No abstract

No abstract

Contextual effects may be important in moderating the expression of psychosis liability in populations, representing a specific pathway independent of the link between common mental disorder and psychosis.

This study has two objectives: One is to demonstrate the Likert-type response scale generation for the Turkish version of the WHOQOL. The other is to show the effect of level of education of the subjects to translate their perception into a rating on a Visual Analog Scale (VAS). WHOQOL questions have four types of response scales: frequency, evaluation, capacity, and intensity. The WHOQOL cross-cultural response scale methodology is based on the VAS. Fifty-one low-level educated subjects from the initial study population (n = 228) were excluded by applying two special exclusion criteria, because of the reliability problems. Those subjects with 8 years and less education were more likely than those with 11 years' (OR = 0.25%; 95 CI 0.11-0.56) and 15 years' and more education (OR = 0.11; 95% CI 0.04-0.29) to be excluded from the study. After translating anchor points into Turkish, the VAS were prepared for each of the response scales (intensity, capacity, frequency, and evaluation). A list of descriptors—16 for frequency, 15 for capacity and intensity, 16 and 14 for evaluation scales—were compiled from dictionaries and the relevant literature. Each descriptor was placed on a 10 cm fresh line in a random order in every scale. The study subjects were asked to place a mark on a 10 cm line for each descriptor, according to where they think the descriptor lies in relation to the anchor points. In order to select the intermediate descriptors for each scale, mean distances for each descriptor were calculated and target intermediate descriptors were found for each scale by applying WHOQOL response scale methodology. The intra-class correlation coefficients (ICC), which indicate the interrater reliability in the current setting, were calculated in the included study population (n = 177) for each education category separately. ICCs were found as 0.39 for 5 years', 0.46 for 8 years', 0.66 for 11 years', and 0.79 for 15 years' and more education categories. Categories of at least 11 years' education were found to show sufficient interrater reliability. The mean and the variabilities of the target descriptors produced similar results with the initial 15 WHOQOL centers. On the other hand, the obtained results indicate that visual analog scale methodology should be used with caution on subjects educated less than 9 years in the Turkish context.