Objective: To test validity and reliability of Personality Diagnostic Questionnaire-fourth vision (PDQ-4) and a self-report DSM-IV axis-II personality disorder (PD) assessing instrument as well as to study the prevalence of personality dysfunction among students of first grade senior high schools in Beijing.
Methods: Among 100 PD patients, 91 non-PD patients with mental disorder, and 100 normal people, sensitivity, specificity and consistency were tested by ICD-10 criteria. By means of stratified cluster sampling, 10 039 students from 25 senior high schools in urban and rural in Beijing were studied using PDQ-4.
Results: PDQ-4 had high sensitivity and moderate specificity for most axis II disorders when compared with ICD-10. Among different samples, PDQ-4 yielded various levels of sensitivity and specificity. Meanwhile, the test-retest consistency was 92.2%. Among 130 adults, the total PDQ-4 score was 18.9 +/- 9.8. The score in males was 20.6 +/- 10.1, versus 17.1 +/- 9.2 in females with significant difference (t = 2.09, P < 0.05). Scores in different age groups were 21.5 +/- 10.5 in age 16 - 25, 16.9 +/- 11.3 in age 26 - 35, 16.4 +/- 9.7 in age 36 - 45, 16.2 +/- 7.9 in age 46 - 55, and 20.0 +/- 7.8 in age 56 and over respectively. No statistical significant difference of scores at age groups was found (F = 2.07, P > 0.05). Among 9 547 students, the total PDQ-4 score was 25.4 +/- 9.6, being significantly higher than that of adult sample. The prevalence of personality dysfunction was 5.6%. Regarding the distribution of personality dysfunction in gender, residential area, and type of school, data showed that the prevalence rates were higher in males, rural area and lower-ranking schools.
Conclusion: PDQ-4 can be used as a PD screen tool in psychiatric institutions and community settings. The distributions of personality dysfunction in Beijing were significantly different on gender, residential area and type of schools. Attention should be paid to personality dysfunction during adolescence.