Understanding patterns and predictors of elevated psychological distress (EPD) among humanitarian migrants compared to the host population is critical for designing effective mental health interventions. However, existing research presents conflicting findings on the prevalence of EPD. This study examined EPD prevalence and associated factors in humanitarian migrants and Australian-born adults using large population-level datasets.

Kessler 6 scores (range 6–30) were dichotomised, and scores above 19 were defined as EPD and indicative of probable serious mental illness. Comparative 1:2 matched analysis used humanitarian migrant data from the Building a New Life in Australia and Australian-born comparators from the National Health Survey. Each humanitarian migrant was matched by age, sex and location with two Australian-born residents. Modified Poisson regression identified predictors of EPD in both groups.

EPD was higher among humanitarian migrants (17.2%, 95% CI: 15.5, 18.9) compared to Australian-born (14.5%, 95% CI: 13.3, 15.6), with an adjusted relative risk (aRR) with 95% confidence intervals (1.16%, 95% CI: 1.11, 1.21) after adjusting for key factors. In both groups, females had a higher aRR than males, with similar effect sizes: 1.06 (95% CI: 1.04, 1.08) among Australian-born and 1.04 (95% CI: 1.02, 1.07) among humanitarian migrants. The impact of age on distress was more pronounced in Australian-born individuals: compared to the 65+ age group, the youngest group (18–24 years) had an aRR of 1.36 (95% CI: 1.28, 1.43) for Australian-born and 1.19 (95% CI: 1.12, 1.27) for humanitarian migrants. Compared to excellent health, poor and fair self-rated health condition had an aRR of 2.13 (95% CI: 2.03, 2.26) and 1.69 (95% CI: 1.61, 1.79), respectively, for humanitarian migrants and 1.94 (95% CI: 1.82, 2.05) and 1.48 (95% CI: 1.43, 1.56), respectively, for Australian born. Australian-born individuals in the lowest-income quintile had higher distress (aRR: 1.11 [95% CI: 1.06–1.15]) compared to the highest-income quintile, with no significant income effect for humanitarian migrants. In both groups, females with poorer self-rated health had higher aRRs than females reporting excellent health.

Although distress prevalence was higher in the humanitarian migrants, age and sex differences followed similar patterns in both groups. Income level was a factor in Australian-born adults but not in humanitarian migrants. Clinically, this highlights the need for culturally sensitive and group-specific mental health support. From a policy perspective, the use of matching methodology from large, separate datasets offers a valuable model for generating actionable insights, supporting the development of targeted and equitable mental health programmes.