TITLE:
The Development of a Short Psychotic Symptoms Questionnaire Using Data of a Two-Wave Epidemiological Study
AUTHORS:
Johannes F. L. M. van Kemenade, Clemens M. H. Hosman
KEYWORDS:
Epidemiology, Longitudinal Design, Psychotic Symptoms, Self-Report Questionnaire, Screener
JOURNAL NAME:
Psychology,
Vol.6 No.16,
December
29,
2015
ABSTRACT: For use in epidemiological surveys, short self-report questionnaires measuring psychotic symptoms were not available in 1995, when we started a multi-wave epidemiological study. This paper presents such an instrument, using the epidemiological data of the 1996 and 2000 waves of a longitudinal study. Relevant items from the Dutch Abbreviated MMPI and the Symptom Checklist were combined into one questionnaire, which was completed by a regional Dutch population sample of 1528 subjects in 1996 and 525 in 2000, with a common cohort of 496. Data from a client sample were used (n = 113) for validation purposes. Principal component analyses resulted in one general psychosis factor with sufficient reliability. Validity research indicated that the instrument measured the psychotic symptoms. Positive correlations were found with schizotypal personality and experienced disability. Correlations indicating both convergent and divergent validity were found in the Rorschach test, the Dutch Abbreviated MMPI and the MMPI-2. The instrument measures the prevalence of psychotic symptoms in the general population and can be used as a short self-report screener in epidemiological surveys. Combined with a disability screener, the proportion of the population suffering disabilitating effects of psychotic symptoms can be estimated. Further research is recommended to investigate the predictive value of the instrument concerning the prognosis of experiencing psychotic symptoms or showing onset of psychotic disorder. This offers perspectives for future use in primary health care to identify persons with psychotic liability or who need support in coping with psychotic symptoms.