The impact of immigration on psychiatric hospitalization in Illinois from 1993 to 2003.

Objective: Illinois public hospitalizations over a ten-year period were studied to determine the impact of recent immigration. The study also explored clinical and demographic differences between immigrant groups and native-born Americans.

Methods: Information was collected from the state hospital Clinical Information System for 1993, 1998, and 2003. Variables included age, sex, race, marital status, education, diagnosis, length of stay, birthplace, citizenship, primary language, English proficiency, and availability of a Social Security number. Logistic multiple regression was used to analyze trends in the proportion of psychiatric admissions of foreign-born patients, with foreign born as the dependent variable and year as the independent variable. Chi square analysis was used for trends across time.

Results: In the hospitalized population, the proportion of immigrants was 7.3% in 1993, 10.9% in 1998, and 13.1% in 2003. With covariates adjusted for, the average increase of 8.0% per year in the odds of being foreign born was statistically significant (odds ratio=1.08, 95% confidence interval=1.06-1.10). Nevertheless, the proportion of foreign-born hospital admissions, including Asian and Mexican immigrants, was below their population ratio in Illinois. Mexican-origin immigrants constituted the largest group of admissions and were younger, less educated, had poorer English skills, and were more likely to be undocumented than other immigrants.

Conclusions: The percentage of foreign-born patients admitted was lower than their percentage in the overall population. In previous immigration waves, immigrants were hospitalized at disproportionately higher rates than nonimmigrants. The gap is slowly narrowing as new admissions are increasingly likely to be foreign born, suggesting that public psychiatric hospitals should prepare for these changing populations.