A study of more than 50 homeless people in Cork city has found that they are more likely to be male, unmarried, unemployed, aged under 65 and to suffer from mental illness.
The report's authors also said it is clear from their research that homeless people run a higher risk of suicide and possibly violence.
The study was published in this month's Irish Medical Journal and was carried out by the Department of Psychiatry at University College Cork.
It found there are significantly higher levels of schizophrenia and substance dependence among the homeless service users in the city, rather than people attending the general adult mental health service.
An examination of the case notes of the 54 people involved in the study also found the group were more likely to have a history of deliberate self-harm.
Researchers said services for homeless people suffering from mental illness in Cork city currently consist of a part-time psychiatrist, two community mental health nurses and a psychologist, but no access to a social worker or occupational therapist.
They warned it is essential that those most at risk receive the essential care they need to reduce morbidity and risk.
