To help explain why some young people move from recreational drug use to substance abuse, twelve in-depth interviews were conducted with young people who had experienced problematic substance use. The data were supplemented by statistical data on 111 young people. The researchers found a variety of "structural" factors that help explain young people's journeys into substance abuse. These included involvement with the state care and protection system, growing up in environments where substance use was either acceptable or encouraged, leaving school early and homelessness. (Contains 1 table.)