A report to be published this week will show that there are huge variations in per capita spending on mental health services across different areas of the State.
The authors of the report by the Irish Psychiatric Association have also found that large per capita increases in funding in certain areas have not resulted in improved services.
The report The Black Hole - A report on the funding attributed to the Irish adult mental health services: where is it actually going? will be published on Thursday. It analyses mental health funding as it is allocated to 31 different geographical areas. It was found that per capita funding in one area of Dublin was 13 times that of Co Kildare, which has the lowest per capita funding of any area in the State.
One of its authors Dr Siobhán Barry said: "There are huge questions about where funding is actually going because there doesn't appear to be any apparent improvement in services."
The report draws on data in the last five annual reports by the Inspector of Mental Hospitals.
Dr Barry said this was the first time that the inspector's findings had been examined sequentially showing how individual services had been funded over five years. The authors have also scientifically analysed funding allocations in relation to measures of social deprivation in different areas in an effort to establish if there was any link between spending levels and deprivation but they found none.
Dr Barry said it was accepted that more resources should be allocated to socially deprived areas than to affluent areas but that their findings confirmed that this was not happening.
Referring to the title of the report The Black Hole, Dr Barry said questions had to be answered and that more investigation was needed to establish if the way money was being spent could be justified. More research was also necessary to establish where funding increases were most needed.
She said there had been a very large increase in funding for some services over the past five years - in some cases more than 250 per cent - while some services had seen their funding decrease.
The last report of the Inspector of Mental Hospitals which covered 2003 showed that funding on mental health services had fallen to 7 per cent of the overall health budget from 13 per cent in 1988. The total amount spent in 2003 was €612 million.
The inspector, Dr Dermot Walsh, also questioned the way money was being spent in that report, saying it was "worth questioning whether our current non-capital expenditure is deployed efficiently".
Dr Walsh also stated: "Some areas with relatively few medical card holders, where most of those seeking psychiatric care do so in the private sector, are relatively lavishly funded compared to others where there are few subscribers to private health insurance and much deprivation. These circumstances are particularly evident in the Dublin area."
Fine Gael TD Dan Neville said he was not surprised at the findings of the report by the Irish Psychiatric Association.
He said it had been shown over many years that in the mental health service the areas of most need had the lowest level of service.