BackgroundAsylum seekers and refugees (ASR) in Germany are dispersed quasi-randomly to state-provided, collective accommodation centres. We aimed to analyse contextual effects of post-migration housing environment on their mental health.MethodsWe drew a balanced random sample of 54 from 1 938 accommodation centres with 70 634 ASR in Germany’s 3rd largest federal state. Individual-level data on depression (PHQ2) and anxiety (GAD2) symptoms as well as sociodemographic- and asylum-related covariates, was collected and linked to contextual geo-referenced data on housing environment (‘Small-area Housing Environment Deterioration’ index, number of residents, remoteness, urbanity and German Index of Multiple Deprivation). We fitted two-level random-intercept models to exploratively estimate adjusted contextual effects.ResultsOf 411 surveyed participants, 45.53% and 44.83%, respectively, reported symptoms of depression or anxiety. 52.8% lived in centres with highest deterioration, 46.2% in centres with >=50 residents, 76.9% in urban, and 56% in deprived districts. 7.4% of centres were remote. The accommodation-level median odds ratio for GAD2 was 2.10 with contextual-level variance of 16%.For odds of reporting GAD2 / PHQ2, the highest degree of deterioration (OR 2.22; 95% CI 0.52-9.59 / 1.99;0.55-7.18), large accommodation size (1.34;0.59-3.06. / 1.12;0.56-2.26), remoteness (2.16;0.32-14.79 / 3.79;0.62-23.18) and district urbanity (3.05;0.98-9.49 / 1.14;0.46-2.79) showed higher, but statistically not significant, point-estimates. District deprivation demonstrated higher odds for GAD2 (1.21;0.51-2.88) and, inversely, lower odds for PHQ2 (0.88;0.41-1.89).ConclusionWe found tendencies for, but no significant, contextual effects of housing environment on ASR mental health in accommodation centres. Confirmatory analyses with prior power calculations are needed to complement these exploratory estimates.Research in contextWhat is already known on this subjectResearch on mental health of asylum seekers and refugees (ASR) has focused on pre- and peri-migratory factors, and increasingly recognizes post-migratory factors and their importance in restoring, sustaining, and protecting health to enable societal integration and participation. Research on the small-area housing environment, and its potential health effects is still scarce, and often limited by high-levels of aggregation of contextual factors, crude or not-standardised measurements on housing characteristics, and risk of compositional bias due to selective migration into housing environments.What this study addsWe make use of the quasi-random allocation of ASR to state-provided, collective accommodation centres, and link individual-level data on health and socio-demographic variables with small-area measures of contextual housing environment at accommodation-level to explore potential effects while minimising the risk of compositional bias. Accommodation-level factors contribute considerably to mental health variance. A tendency towards higher odds of reporting symptoms of generalized anxiety could be observed for housing deterioration, higher numbers of residents, remoteness as well as district urbanity and deprivation. Similar tendencies were estimated for reporting symptoms of depression except for deprivation potentially functioning protectively. Confirmatory research with appropriate sample size calculations as well as mediation and structural equation analysis are needed. Results may guide policy makers in design and planning of needs-based health services and housing infrastructure.