The number opiate users in the State rose by more than 41 per cent between 2001 and 2006, according to a study by the National Advisory Committee on Drugs (NACD).
But researchers said the rise was partially inflated by an expansion of the national methadone treatment programme and the statistical model used to collate the figures.
The report, published today, indicated there were 11,807 known opiate users in the country in 2006 and a possible further 8,983 “unknown” users, who have not come into contact with various drug treatment services, hospital in-patient services or the gardaí.
This represents a rise 6,109 on the 14,681 reported opiate users in the 2001 survey.
However, the NACD urged a “considerable degree of caution” in interpreting the figures as the population of the survey was not fixed and there was a diminishing overlap between the three sources used, which meant the 2006 figure overestimated the prevalence of opiate abuse in Ireland.
The study showed the rate of opiate use among young people aged 15-24 decreased during the five-year period, suggesting the shifting age profile of opiate users, and significantly a reduction in the number of young people commencing opiate use.
But it also showed a significant rise in rate of opiate use outside of Dublin.
The study found a higher proportion of opiate users were in treatment in Dublin than elsewhere, “reflecting the more recent spread of opiate use outside Dublin and the later development of treatment services”.
Minister of State with responsibility for the national drugs strategy, John Curran, said: Minister Curran said: "The general consensus is that, while opiate use has been relatively stable in the Dublin area over the last number of years, its use has become more widely dispersed around the country.
“This is borne out by the experience of service providers, the fact that the rate of new entrants to treatment had dropped significantly (by approximately 20% between 2001/02 and 2006/07) and the fact that the average age of those in treatment had increased from 28 to 33 in the same period,” he said.
NACD chairman Dr Des Corrigan said that the research highlighted the need for continued investment in existing opiate treatment services, including the expansion of opiate treatment services outside of Dublin.
A recent joint initiative of the HSE and the Office of the Minister for Drugs will see major improvements in treatment provision in locations around the country, including Tralee, Cork, Waterford, Enniscorthy, Drogheda and Dundalk, he said.