The analysis focused on the prevalence of illicit drug use beyond experimentation and examined the “capture rates” of marijuana, amphetamines, ecstasy, and cocaine. The participants attended eight secondary schools in three boroughs in London. Results revealed that the transition rate from opportunity to use to actual use was most pronounced for marijuana, which had a capture rate of one in five. The transition rate was next highest for amphetamines, followed by ecstasy and finally by cocaine. However, regular use as a result of having ever used was lowest for amphetamines and cocaine. Age appeared to be a protective factor, because the average age of those who had never been offered drugs was consistently under age 15. In contrast, early onset of drinking alcohol and smoking tobacco appeared to be a risk factor among those who were offered marijuana and became regular users. Findings suggested the need to target early interventions and educational initiatives to those with early onset and rapid escalation in drinking and tobacco use. 16 references