Ethnic Differences in Mental Illness Severity: A Population-Based Study of Chinese and South Asian Patients in Ontario, Canada

Objective: Little is known about the sociocultural determinants of mental illness at hospital presentation. Our objective was to examine ethnic differences in illness severity at hospital admission among Chinese, South Asian, and the general population living in Ontario, Canada.

Methods: We conducted a large, population-based, cross-sectional study of psychiatric inpatients aged from 19 to 105 years who were discharged between 2006 and 2014. A total of 133,588 patients were classified as Chinese (n = 2,582), South Asian (n = 2,452), or the reference group (n = 128,554) using a validated surnames algorithm (specificity: 99.7%). Diagnoses were based on DSM-IV criteria. We examined the association between ethnicity and 4 measures of disease severity: involuntary admissions, aggressive behaviors, and the number and frequency of positive symptoms (ie, hallucinations, command hallucinations, delusions, and abnormal thought process) (Positive Symptoms Scale, Resident Assessment Instrument-Mental Health [RAI-MH]).

Results: After adjusting for sociodemographic characteristics, immigration status, and discharge diagnosis, Chinese patients had greater odds of involuntary admissions (odds ratio [OR] = 1.79; 95% CI, 1.64-1.95) and exhibiting severe aggressive behaviors (OR = 1.36; 95% CI, 1.23-1.51) and ≥ 3 positive symptoms (OR = 1.39; 95% CI, 1.24-1.56) compared to the general population. South Asian ethnicity was also an independent predictor of most illness severity measures. The association between Chinese ethnicity and illness severity was consistent across sex, diagnostic and immigrant categories, and first-episode hospitalization.

Conclusions: Chinese and South Asian ethnicities are independent predictors of illness severity at hospital presentation. Understanding the role of patient, family, and health system factors in determining the threshold for hospitalization is an important future step in informing culturally specific care for these large and growing populations worldwide.