There is an uneven distribution of psychiatric services in the State, with those in the eastern region showing significant signs of strain, according to a study in the Irish Journal of Psychological Medicine.
The study found a five-fold difference in overall bed and hostel numbers between health boards, with the Eastern Regional Health Authority area having significantly less resources than other regions.
Researchers at the Central Mental Hospital in Dundrum compared variations in the provision of psychiatric beds and other facilities with the numbers of patients admitted to the hospital via the prisons and the courts from each health board area.
Of the 476 admissions to the hospital between 1997 and 1999, a disproportionate number came from the catchment area of the former Eastern Health Board (now the ERHA). Consultant forensic psychiatrist at the Central Mental Hospital, Dr Harry Kennedy, and his co-authors based their study on the premise that an increase in the number of mentally ill patients admitted to the forensic psychiatric service was a sign that overall psychiatric resources were under pressure.
This relates to the view that "strained psychiatric services are likely to fail to intervene early in the course of an episode of mental illness, leading to increased prison committal rates for the mentally ill from that catchment area".
The results showed a much higher admission rate to the Central Mental Hospital of patients from the ERHA area - 11.5 per 100,000 population compared to the national average of 6.7.
There was also an inverse relationship between the number of general psychiatric beds in the health board and the possibility of a patient being admitted to the Central Mental Hospital: those health boards with the highest numbers of psychiatric beds and hostel resources had the lowest rate of admissions.
The eastern region had the lowest number of general assessment beds and hostel places and the lowest per capita funding.
A further sign of a strained service was the higher annual bed turnover - the number of admissions per general psychiatric bed - in the eastern region.
Dr Kennedy said: "We believe that the study shows strain in psychiatric services in the eastern region, which has the least number of beds and hostel places, despite having the highest indices for deprivation."
He noted that patients admitted from the ERHA area via the courts and prisons were more likely to have a serious mental disorder, such as schizophrenia or bipolar illness.
They were also more likely to be charged with minor offences than those from other health board areas.
"These findings do not mean that rural health boards are over budget but rather that mental health services in the greater Dublin area are underfunded," Dr Kennedy said. "What appears to have happened is that as in-patient beds were closed, no commissioning process for compensatory community facilities was put in place prior to the establishment of the ERHA in January 2000," he added.