Homeless people suffer from high rates of mental health problems exacerbated by living on the streets and in shelters. The lack of residential stability makes care delivery more complicated. Approximately half of homeless people suffer from mental health issues. At a given point in time, 45 percent of homeless report indicators of mental health problems during the past year, and 57 percent report having had a mental health problem during their lifetime. About 25 percent of the homelessness population has serious mental illness, including such diagnoses as chronic depression, bipolar disorder, schizophrenia, schizoaffective disorders, and severe personality disorders.
Many homeless people have problems with drug and alcohol use.
In a 1996 survey, 46 percent of the homeless respondents had an alcohol use problem during the past year, and 62 percent had an alcohol use problem at some point in their lifetime.