Prevalence of high-risk symptoms for psychosis in population of adolescents: Czech version of The Prodromal Questionnaire Brief
Abstract
Background. Identification of individuals at high risk of psychotic disorder can help to prevent onset of the disorder.
Objectives. To examine both psychometric characteristics of the Czech version of The Prodromal Questionnaire Brief Version (PQB) and prevalence of risk symptoms for psychosis among Czech adolescents.
Sample and methods. The PQB was administered to a sample of students in Prague (grammar and secondary vocational schools-SVS and apprentice training centers-ATC) aged 15-20 years.
The PQB consists of 21 items. The cut-off score for positive screening (PQB+) was set as >= 8 items, the cut-off score >= 8 positive symptoms with significant distress was set for PQB distress + and the cut-off score >= 24 for total distress for PQB total distress +.
Statistical analysis. Cronbach alpha, item analysis and exploratory factor analysis were used for reliability estimation of the PQB.
Exploratory analyses using Fisher's exact test, Mann-Whitney test, Pearson chi square test, and Kruskal- Wallis test were used as appropriate for testing between group differences in the PQB scores. Results.
Data from 435 students were analyzed (mean age 17.2 +/- 1.0 years). Sample consisted of 249 males (54%) and 216 females (46%).
Sex distribution among schools differed (female, grammar schools 49% vs. ATC 87% vs.
SVS 31%, p<0.001), but age distribution did not (p=0.08). Cronbach alpha of the PQB was 0.85, and three-dimensional factor structure was found.
Factor 1 was made up of 7 (factor load 0.444-0.729; Cronbach alpha=0.73), factor 2 of 6 (factor load 0.404-0.721; alpha=0.73), and factor 3 of 4 items (factor load 0.313-0.618; alpha=0.65). 204 subjects in the total sample were PQB+ (44%), 44 were PQB distress+ (9%) and 174 were PQB total disnms + (37%). Study limitation.
Generalization of study results is limited, since only students from Prague high schools were assessed.