Validation of a Spanish version of the Schizotypal Personality Questionnaire (SPQ): Psychometric characteristics and underlying factor structure derived from a healthy university student sample.

Objective: The need for early detection, prevention and intervention in psychosis has prompted the study of prodromal and threshold syndromes. One strategy involves the assessment of schizotypy, a personality construct involving unusual perceptual experiences, magical thinking or bizarre behavior. Sensitive measurement instruments could potentially allow detection of signs heralding transition to psychosis in high-risk individuals, or risk of relapse in patients after a first psychotic episode. The Schizotypal Personality Questionnaire (SPQ) is a self-report scale, originally developed for English speakers, that covers the nine DSM-IV criteria for schizotypal personality disorder (SPD). Our aim was to validate a Spanish version of the SPQ and assess its psychometric properties.
Methods: The original SPQ was back-translated and administered to university students (n=250). We assessed the internal consistency, the convergent, discriminant and criterion validity of the instrument, and analyzed its factor structure.
Results: Our version of the SPQ showed good internal consistency, and convergent (O-LIFE), discriminant (P-scale of EPQ) and criterion validity (SCID-II). Factor analyses supported a four-factor structure in fitting SPQ data.
Conclusions: Our Spanish version of the SPQ questionnaire preserved the psychometric properties of the original questionnaire. This adaptation will provide a useful tool for the early detection of prodromal schizophrenia symptoms and clinical relapse in Spanish-speaking populations.