Gender-stratified national mental health norms of BSI-53, BSI-18, SCL-10, ADHD-9, and ADHD-6 for Denmark

BACKGROUND: Reliable gender-sensitive normative data is needed to facilitate mental health research and clinical utility of commonly used symptoms scales. This study establishes Danish gender-stratified norms for the 53-item and 18-item Brief Symptom Inventory (BSI-53, BSI-18), proposed attention deficit hyperactivity disorder (ADHD) symptomatology scales from the BSI-53, and the 10-item Symptom Checklist (SCL-10). This study also examines gender-differences in symptom reporting of the ADHD and SCL-10 scales, and assesses potential bias in recent SCL-10 norms.

METHODS: Norms for the BSI-53, BSI-18, two ADHD scales and SCL-10 were established using archived Hopkins Symptom Checklist 90-R (SCL-90R) normative data collected in spring 2000 (n = 1079, age 18-80, 53% female). SCL-10 norms from 2000 were compared with proposed norms collected in spring 2020 (n = 2819, age 18-80, 55% female) during the first COVID-19 lockdown in Denmark, and with first-episode depression patients from 2020 to 2023 (n = 221, age 18-65, 73% female).

RESULTS: The scales showed high internal consistencies (McDonald's ω > 0.81), except for 4-5 item scales (ω > 0.73). Women scored higher on both ADHD scales (Cohen's d = 0.15 and 0.19, p ≤ 0.019). Women scored higher on the SCL-10 in the 2000 population sample (d = 0.22, p < 0.0001) and in patients (d = 0.44, p = 0.004). The average population SCL-10 score in 2000 was lower than 2020 (d = 0.52, p < 0.001).

CONCLUSION: This study provides gender-stratified Danish mental health norms for multiple symptom scales. The considerable gender differences in the SCL-10 underscore the importance of gender-specific norms. The 2020 SCL-10 norms are biased by COVID-19 distress. Until new normative data is available, the gender-specific norms provided here are recommended.