Assessing Psychological Distress with BSI

General psychological symptoms were assessed using the Symptom Checklist-90-Revised [21 ] at baseline, and its abbreviated version, the Brief Symptom Inventory (BSI) [22 ], at follow-up. Both versions are based on identical items and have been shown to present fairly equivalent psychometric properties [23 (link), 24 (link)]. Hence, we focused our analyses on the BSI. The BSI is a widely used 53-item measure of subjective psychological distress experienced in the preceding seven days. All responses are scored on a 5-point scale from 0 (“not at all”) to 4 (“extremely”). The BSI’s nine subscales cover symptoms of clinically relevant psychological syndromes: somatization, obsessive-compulsive disorder, interpersonal sensitivity, depression, anxiety, phobic anxiety, paranoid ideation, and psychoticism. The Global Severity Index (GSI) is a measure of overall psychological distress and is calculated by summing up all nine subscales. Urbán and colleagues [24 (link)] proposed a bifactor model that supports reporting the nine subscales in addition to the rather sound GSI as outcome measures. In this study, Cronbach’s alpha of the GSI was .97 and .96 at baseline and follow-up, respectively.