Up to 1,000 people in Northern Ireland are problem heroin users, a new report published today shows.
The survey also revealed that up to two-thirds of users did not receive any treatment for their addiction in the 12-month period of study.
Users in Ballymena, Co Antrim, were more likely to be male, younger, and injecting more than in other areas, while users in Belfast were more likely to smoke than inject.
It is the first study of its kind into the scale of usage.
Northern Ireland Drug and Alcohol Co-ordinator Ms Jo Daykin said: "It provides a reliable baseline of the number of problem heroin users. This will enable us to more effectively plan and target services."
The report estimated the number of problem heroin users in a 12-month period from November 2000 to October 2001.
Problem users are described as individuals who had experienced significant "social, psychological, physical or legal problems associated with dependence, intoxication or regular consumption" of heroin.
It was found that during the 12-month period of the study, between 36 and 52 per cent of problem heroin users received treatment.
The study was commissioned by the Drug and Alcohol Unit of the Department of Health and was carried out by Dr Karen McElrath of Queen's University in Belfast.
PA