People who live in deprived areas are far more likely to use heroin than people in better-off areas, the TCD health inequality report suggests.
It also suggests the growth of a large underclass of single males in Dublin with very poor health.
One of the five data bases analysed by the authors found a very strong correlation between treatment for the abuse of opiate drugs - including heroin - and living in an area of high social deprivation.
Area deprivation was measured using the Small Area Health Research Unit deprivation index - which measures material deprivation. The authors plotted the relationship between this deprivation index and a measure of those people attending for heroin addiction treatment. The result showed a very high probability of undergoing drug rehabilitation treatment if you lived in areas of high deprivation.
People aged 15 - 34 living in areas of the inner city, Tallaght and Priorswood were up to three times more likely to undergo treatment for heroin abuse than people living in Clontarf, Ballsbridge or Dun Laoghaire.
The report's authors also found a strong link between socio-economic status and the incidence of psychiatric conditions. A comparison of admission data to psychiatric units found that a person was four times as likely to be admitted to hospital for schizophrenia if he/she was in the unskilled manual category than for higher professionals.
Prof Tom O'Dowd, one of the authors, said he was concerned at the very high number of people with psychiatric conditions who are classified as "unknown" in socio-economic analysis. "This could be evidence for a growing number of 'excluded', or an underclass in Irish society," he said.
When hospital discharge figures for all psychiatric conditions were combined and set against figures for each county in the Republic, no discernible geographic pattern could be found. The incidence of alcoholic disorders amongst all professional groups showed no change between 1991 and 1996.