Objectives. The aim of study was to test (a) the factorial structure of the BSI-18 instrument, (b) its basic psychometric attributes, (c) effect of gender, age, average monthly household income, and faith in God using representative sample of Czech respondents without declared somatic and psychiatric diagnosis.
Subjects and setting. Responses were obtained from a representative sample of 1841 Czech persons (898 males, 943 females), average age 46,53; SD = 17,68, chosen using random quota sampling based on gender, age, and region.
Results. Based on Czech representative general population the BSI-18 looks like internally consistent, unidimensional inventory.
The factorial structure was not statistically influenced by gender, age, monthly income, and faith in God. The association of age and gender with Global Severity Index was not statistically significant.
The effect of monthly income was nonlinear, respondents with highest and lowest income reported higher psychological distress in comparison with the respondents with average income. Likewise, the believers in God recorded a statistically significantly higher degree of distress compared to the unbelievers.
Conclusion. The instrument can be used to reliably evaluate the psychological distress in the general population and the findings can also serve as a framework of reference for assessing the severity of distress in clinical trials.
Study limitation. The findings are limited to a Czech general representative population sample.