The study, published in the medical journal Social Psychiatry and Psychiatric Epidemiology, was conducted in Bordeaux state hospital in France.
That study also found that most of the homeless people admitted to the clinic had already been identified by mental health services as suffering from a severe mental illness, suggesting that homelessness was a consequence of losing contact with mental health support.
Among those homeless people with psychosis, there was an over-representation of men, and people with drug addictions.
The actual number of homeless people with psychosis may actually be higher, as clinic samples tend to under-estimate the extent of mental health problems in the population, owing to the fact that people who go to clinics tend to be there for immediate help for current difficulties.
Link to abstract of scientific paper.