The Brief Symptom Inventory-9 (BSI-9): Development and validation in a German general population sample

The Brief Symptom Inventory-18 (BSI-18) is a self-report questionnaire with three subscales, somatisation, anxiety, and depression, based on longer measures of distress. The present study proposes a shorter, nine-item version (BSI-9) of the BSI-18 as a brief screening tool for distress.

Confirmatory factor analyses and reliability and validity analyses were carried out using a representative sample of the German general population. Confirmatory factor analysis demonstrates a good model fit for the three-dimensional BSI-9.

The total scale was found to have strong internal consistency (α_Cronbach = 0.87 for the global severity index). The internal consistency coefficients of the three-item subscales reflect the brevity of these scales (somatisation α_Cronbach = 0.72, depression α _Cronbach = 0.79, anxiety α_Cronbach = 0.68). The subscales were found to be significantly related with subscales of the Patient Health Questionnaire-4 and Hopkins Symptom Checklist-25.

The present study used a limited number of distress measures, and a more recent dataset would be useful to provide a more current picture of the general population's distress levels.

The BSI-9 provides a short, valid, and reliable screener for distress in the general population. Future work should examine its utility in clinical settings and different cultural contexts.