Screening for infectious diseases among patients in a state psychiatric hospital. 
This cross-sectional retrospective study examined the frequency of positive tests for infectious diseases among 655 patients who were admitted to a state psychiatric hospital from 1997 to 1999.  Not all patients who were admitted to the hospital were tested for each disease.  Rates of positive tuberculin (20.2 percent), hepatitis B (23.9 percent), and hepatitis C (21.5 percent) tests were all significantly greater than estimates for the U.S. general population.  A minority of patients were tested for HIV, and 29.0 percent were positive.  The rate of hepatitis A was similar to that in the general population (33.2 percent).  Independent risk factors for markers of disease included age, immigrant status, homelessness, and history of substance use.  These results confirm the importance of screening for infectious diseases among individuals with severe and persistent mental illness.