Examining variations in the prevalence of diagnosed mood or anxiety disorders among migrant groups in Ontario, 1995-2015: a population-based, repeated cross-sectional study

Background — International evidence on the frequency of mood or anxiety disorders among migrant groups is highly variable, as it is dependent on the time since migration and the socio-political context of the host country. Our objective was to estimate trends in the prevalence of diagnosed mood or anxiety disorders among recent (<5 years in Canada) and settled (5-10 years in Canada) migrant groups, relative to the general population of Ontario, Canada.

Methods — We used a repeated cross-sectional design consisting of four cross-sections spanning 5 years each, constructed using health administrative databases from 1995 to 2015. We included all Ontario residents between the ages of 16 and 64 years. We assessed differences in the prevalence of mood or anxiety disorders adjusting for age, sex, and neighbourhood-level income. We further evaluated the impact of migrant class and region of birth.

Results — The prevalence of mood or anxiety disorders was lower among recent (weighted mean = 4.10%; 95% confidence interval [CI], 3.59% to 4.60%) and settled (weighted mean = 4.77%; 95% CI, 3.94% to 5.61%) migrant groups, relative to the general population (weighted mean = 7.39%; 95% CI, 6.83% to 7.94%). Prevalence estimates varied greatly by region of birth and migrant class. We found variation in prevalence estimates over time, with refugee groups having the largest increases between 1995 and 2015.

Conclusions — Our findings highlight the complexity of mood and anxiety disorders among migrant groups, and that not all groups share the same risk profile. These results can be used to help inform health service allocation and the development of supportive programs for specific migrant groups.