The validity of the Schizotypal Personality Questionnaire in a Greek sample: Tests of measurement invariance and latent mean differences.
BACKGROUND
The Schizotypal Personality Questionnaire (SPQ) is a widely used scale for measuring schizotypal characteristics modeled on DSM-III-R criteria for schizotypal personality disorder (SPD). The aim of this study was to examine the factorial structure of the Greek SPQ, its factorial invariance across gender and different age groups and possible gender and age group differences at latent mean level.


METHODS
Eight hundred sixty-five community participants completed the Greek version of the SPQ.


RESULTS
With regard to the factorial structure of the original first-order model, the results showed that a seven-factor model (sub-scales "no close friends" with "constricted affect" and "ideas of reference" with "unusual perceptual experiences" were combined) was replicated adequately. Furthermore, the second-order "paranoid" model provided also adequate fit. With regard to the factorial invariance of the SPQ across gender and age, the analysis revealed that both, the first- and second-order models showed measurement invariance (configural, metric and structural) across gender and age groups (17-35 vs. 36-70). Latent mean differences across gender and age groups were also found.


CONCLUSIONS
Based on these findings, we can conclude that the Greek version of the SPQ is a psychometrically sound instrument for measuring schizotypal characteristics and a useful screening tool for SPD across gender and age.
Department of Psychology, University of Crete, Rethymno, Crete, Greece. Electronic address: tsaousis@uoc.gr.
Ioannis
I
Tsaousis
Department of Psychology, University of Crete, Rethymno, Crete, Greece.
Chrysoula
C
Zouraraki
Department of Psychology, University of Crete, Rethymno, Crete, Greece.
Penny
P
Karamaouna
Department of Psychology, University of Crete, Rethymno, Crete, Greece.
Leda
L
Karagiannopoulou
Department of Psychology, University of Crete, Rethymno, Crete, Greece.
Stella G
SG
Giakoumaki
D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D039721:Diagnostic and Statistical Manual of Mental Disorders; D005006:Ethnicity; D005260:Female; D006115:Greece; D006801:Humans; D008297:Male; D008875:Middle Aged; D008960:Models, Psychological; D010555:Personality Inventory / Q000592:standards*; D011594:Psychometrics; D012569:Schizotypal Personality Disorder / Q000175:diagnosis* / Q000523:psychology; D012737:Sex Factors; D055815:Young Adult