Measurement Invariance of and Mean Differences on the Kessler Psychological Distress Scale (K6) for LGBT and Cisgender, Heterosexual Individuals

The Kessler Psychological Distress Scale (K6) is used as a self-report measure of nonspecific psychological distress. Although research documents higher K6 scores among lesbian, gay, bisexual, and transgender (LGBT) individuals relative to cisgender, heterosexual individuals, measurement invariance of the K6 has not been established between these groups. We used multigroup confirmatory factor analysis to examine factorial invariance of the K6 between 1,765 LGBT and 20,632 cisgender, heterosexual individuals who completed the Well-Being and Basic Needs Survey. The K6 exhibited configural, weak/metric, and strong/scalar measurement invariance between groups, suggesting that it operates equivalently for both groups. We then examined differences in latent mean K6 scores between groups and differences in the percentage of individuals in each group who met a threshold for serious psychological distress (scores ≥ 13). The latent K6 mean and the percentage of individuals who met the threshold for serious psychological distress were both significantly higher for LGBT than for cisgender, heterosexual individuals.