An assessment of the nature and extent of drug abuse has been based on an analysis of different indicators, including the incidence of people seeking treatment for drug dependency, hepatitis, drug seizures, prosecutions, hospital casualty department visits, and drug-related deaths. Surveys of schoolchildren and young people indicate a 600 percent increase in drug experimentation, while the number of heroin and other opiate addicts seeking treatment increased five to six times between 1979 and 1983. According to a recent study conducted in northern Dublin, 10 percent of people aged 15 to 24 were addicted to heroin, although another study found that only 2.2 percent of the youth in a southern Dublin suburb were heroin users. The author suggests the major risk factor underlying heroin abuse among young people is disrupted family life. 22 references. (Author abstract modified)