Patterns of drug use may change over time. Many European cities have reported increases in the number of young drug users seeking treatment in the 1990s, and increasing numbers of users are choosing to smoke or "chase the dragon" rather than inject.

This article examines trends in treated opiate misuse and identifies factors associated with the route of heroin use. The database of the National Drug Treatment Reporting System database was used for this cross sectional survey. Individuals were included if they were resident in Dublin between January 1991 and December 1996, were making their first treatment contact, and reporting current use of an opiate as their principle drug of abuse. 3981 people made these criteria. The Mantel-Haenzel chi squared test for linear trend was used to examine for the presence of temporal trends in categorical variables. Multivariate analysis was performed using logistic regression. 77.5% were male and the mean age was 21.5 years. The unemployment rate was 88.2% and 29.9% ceased school attendance before the legal minimum school leaving age of 15.

The mean age for commencement of opiate use was 18.7 years and the mean duration of use was 2.6 years. Over a 6-year period there was a 330% increase in the number of new attenders for treatment, and the proportion of females increased. The mean age of first opiate use declined and users began to present for treatment at an earlier stage in their opiate-using career. After 1994 heroin users were more likely to smoke the drug rather than inject it. Like other European countries, Ireland is displaying the trend towards increased chasing. This trend coincides with the increased number of young users presenting for treatment and may indicate that this "more acceptable" method of using heroin (compared with intravenous injecting) may be luring an increased number of individuals into heroin use.