Psychosis-proneness or schizotypy is a personality organisation mirroring individual risk for schizophrenia-development. Believed to be a fully dimensional construct sharing considerable geno- and phenotypal variance with clinical schizophrenia, it has become an increasingly promising tool for basic psychosis-research. Although many studies show genetic commonalities between schizotypy and schizophrenia, changes in regulation of gene expression have never been examined in schizotypy before. We therefore extracted RNA from the blood, a valid surrogate for brain tissue, of a large sample of 67 healthy male volunteers and correlated the activities of all genes relevant for dopaminergic neurotransmission with the positive schizotypy-scale of the O-LIFE. We found significant negative correlations regarding the expression of the genes COMT, MAOB, DRD4, DRD5 and FOS, indicating that increased schizotypy coincides with higher levels of dopaminergic dysregulation on the mRNA-level. Considering the advantages of this method, we suggest that it be applied more often in fundamental psychosis-research.

Anhedonia, a central dimension within the schizotypy construct, has been considered to be a promising vulnerability marker for schizophrenia-spectrum disorders. The Revised Physical Anhedonia Scale (RPhA) and Revised Social Anhedonia Scale (RSAS) are two self-reports widely used in the assessment of anhedonia; however, they psychometric characteristics have been scarcely investigated in Spanish population. The objective of the current work was to study the psychometric properties of the Revised Physical and Social Anhedonia Scales in non-clinical young adults. The sample was composed of 728 college students with a mean age of 20.1 years (SD=2.5. The data indicated that the scales showed adequate psychometric characteristics. The Cronbach alpha was 0.95 (RSAS) and 0.92 (RPhA) respectively. The confirmatory factor analysis carried out on the matrix of tetrachoric correlations showed that both scales presented an essentially unidimensional solution. The Revised Physical and Social Anhedonia Scales seem to be adequate for psychosis-risk assessment in non-clinical populations. Future research should further investigate the construct validity in other populations and cultures as well as study its relation to emotional aspects and cognitive endophenotypes.

The Wisconsin Schizotypy Scales are among the most widely used instruments for the assessment of psychosis proneness. The main goal of the present work was to study the dimensional structure underlying the Revised Physical Anhedonia Scale (RPhA), the Revised Social Anhedonia Scale (RSAS), the Magical Ideation Scale (MIS) and the Perceptual Aberration Scale (PAS). It was also explored whether the dimensions underlying these scales were invariant across gender and age. The sample was made up of 710 university students with a mean age of 19.8 years (SD = 1.9). The results showed that the dimensional structure of the Wisconsin scales was similar to that found in previous studies, displaying a Positive dimension and a Negative dimension, the Social Anhedonia Scale being related to both dimensions. Moreover, the factor structure of the schizotypy scales was found to be invariant across participants' gender and age.

The main goal of this research was to examine the reliability and different sources of validity evidence of the Oviedo Schizotypy Assessment Questionnaire-Abbreviated (ESQUIZO-Q-A) in nonclinical adolescents. The final sample was made up of 1,455 participants, 705 males (48.5%), with a mean age of 15.92 years (SD = 1.18). The internal consistency of the subscales ranged from .62 to .75. The analysis of its internal structure yielded a three-dimensional solution based on the dimensions: Reality Distortion, Anhedonia, and Interpersonal Disorganization. Likewise, the goodness-of-fit indices derived from the Confirmatory Factor Analysis for the hypothesized three-factor model were adequate. The three dimensions of the ESQUIZO-Q-A were significantly correlated with the subscales of the Strengths and Difficulties Questionnaire. The ESQUIZO-Q is a brief and simple self-report with adequate psychometric properties for the assessment of schizotypal traits in nonclinical adolescent populations. Future research should continue to explore the metric quality of the ESQUIZO-Q-A (e.g., sensitivity and specificity) and incorporate the new advances in psychological and educational assessment such as Computerized Adaptive Testing.