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

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. 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 (<i>n</i> = 1079, age 18–80, 53% female). SCL-10 norms from 2000 were compared with proposed norms collected in spring 2020 (<i>n</i> = 2819, age 18–80, 55% female) during the first COVID-19 lockdown in Denmark, and with first-episode depression patients from 2020 to 2023 (<i>n</i> = 221, age 18–65, 73% female). The scales showed high internal consistencies (McDonald’s <i>ω</i> &gt; 0.81), except for 4–5 item scales (<i>ω</i> &gt; 0.73). Women scored higher on both ADHD scales (Cohen’s <i>d</i> = 0.15 and 0.19, <i>p</i> ≤ 0.019). Women scored higher on the SCL-10 in the 2000 population sample (<i>d</i> = 0.22, <i>p</i> &lt; 0.0001) and in patients (<i>d</i> = 0.44, <i>p</i> = 0.004). The average population SCL-10 score in 2000 was lower than 2020 (<i>d</i> = 0.52, <i>p</i> &lt; 0.001). 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.