The rate of drug-induced deaths in Ireland (53.5 per million population) is more than twice the EU average (21.7) and is higher than Britain (49).
In contrast, the Netherlands has one of the lowest mortality rates in Europe (8.7).
In its 2009 annual report, the European Centre for Drugs and Drug Addiction (EMCDDA) said Ireland was fifth out of 30 European countries.
Luxembourg was top (85.3), followed by Estonia (74.2), Norway (72.1), Denmark (57.7) and Ireland.
The report said the last figures for Ireland showed there were 159 drug-induced deaths in 2005.
EMCDDA expert Roland Simon said the figures were comparable, as all countries provided data based on the same guidelines. He said there could be a number of factors behind countries, such as Ireland, with relatively high death rates.
“Countries may have a relatively high rate of drug use. There may also be a relatively high rate of intravenous drug use. So, countries may have the same level of drug use, but with different mode of administration. For example, the Dutch always had a tradition of smoking and inhaling, much less i/v drug use, compared to other countries.”
The Irish Health Research Board (HRB), which supplied information to the EMCDDA, said that 70% of fatal overdoses in Ireland were associated with opiate use, including heroin and methadone.
It said 29% of drug-induced deaths were as a result of cocaine poisoning.
EMCDDA scientist Paul Griffiths said the continuing high number of heroin deaths in the EU was a cause of “real concern” given a dramatic increase in treatment provision and a reduction in injecting.
The annual report said possible reasons include an ageing and more chronic population and increased levels of polydrug use.
The report said there was a growing concern about heroin use, not helped by massive overproduction of opium in Afghanistan in recent years.
The HRB said the number of new opiate treatment cases had jumped by 67%, from 809 in 2002 to 1,350 in 2008.