title: Schizotypal traits in adolescents with 22q11.2 deletion syndrome: validity, reliability and risk for psychosis.
abstract: BACKGROUND
  Very little is known about the phenotypic expression of schizotypal traits in individuals with 22q11.2 deletion syndrome (22q11DS). The main purpose was to analyse the factorial structure, internal consistency and temporal stability of schizotypal traits, as well as their associations with prodromal states and clinical psychotic symptoms in adolescents with 22q11DS.
  
  
  METHODS
  The sample comprised 61 adolescents with 22q11DS (mean = 14.95 years, s.d. = 2.13; n = 24 at follow-up). An age-matched comparison group (n = 61, mean = 15.44 years, s.d. = 1.76) was also included. The Schizotypal Personality Questionnaire (SPQ), the Structured Interview for Prodromal Syndromes, the Positive and Negative Syndrome Scale, and the Brief Psychiatric Rating Scale were used.
  
  
  RESULTS
  Adolescents with 22q11DS scored higher than the control group on the interpersonal dimension and suspiciousness subscale of the SPQ. The analysis of the internal structure of the SPQ in the sample of 22q11DS participants yielded a three-component solution (cognitive-perceptual, interpersonal, and disorganized). In addition, internal consistency coefficients ranged between 0.63 and 0.91. The schizotypal traits were highly stable across a 3.6-year interval, and ranged from 0.50 to 0.63. Self-reported schizotypal traits correlated with interview-based ratings of prodromal states and psychotic symptoms.
  
  
  CONCLUSIONS
  These results indicate that the SPQ may be a valid tool to assess schizotypal traits in adolescents with 22q11DS. The identification of a reliable self-report instrument for use in individuals with learning disabilities and at genetic high risk for psychosis could be useful in clinical and research settings. Assessment of schizotypal traits may be used as a distal risk marker and in a close-in strategy in high-risk genetic samples to enhance the possibility of early detection of psychosis.
authors.affiliation: Department of Educational Sciences,University of La Rioja,La Rioja,Spain.
authors.forename: E
authors.initials: E
authors.lastname: Fonseca-Pedrero
authors.affiliation: Developmental Clinical Psychology Research Unit,Faculty of Psychology and Educational Sciences,University of Geneva,Geneva,Switzerland.
authors.forename: M
authors.initials: M
authors.lastname: Debbané
authors.affiliation: Department of Psychiatry,Office Médico-Pédagogique Research Unit,University of Geneva School of Medicine,Geneva,Switzerland.
authors.forename: M
authors.initials: M
authors.lastname: Schneider
authors.affiliation: Developmental Clinical Psychology Research Unit,Faculty of Psychology and Educational Sciences,University of Geneva,Geneva,Switzerland.
authors.forename: D
authors.initials: D
authors.lastname: Badoud
authors.affiliation: Department of Psychiatry,Office Médico-Pédagogique Research Unit,University of Geneva School of Medicine,Geneva,Switzerland.
authors.forename: S
authors.initials: S
authors.lastname: Eliez
mesh_terms: D000293:Adolescent; D016022:Case-Control Studies; D004062:DiGeorge Syndrome / Q000523:psychology*; D005260:Female; D006801:Humans; D008297:Male; D010641:Phenotype; D062706:Prodromal Symptoms; D011569:Psychiatric Status Rating Scales; D011594:Psychometrics / Q000379:methods*; D015203:Reproducibility of Results; D012307:Risk Factors; D012569:Schizotypal Personality Disorder / Q000175:diagnosis*; D057566:Self Report
keywords: 22q11.2 deletion syndrome; Adolescents; psychotic symptoms; risk markers; schizotypal traits; schizotypy