Some insights drawn from statistical analyses conducted by the French Monitoring Center for Drugs and Drug Addiction (OFDT) between 2004 and 2008 to cross-reference the results of a quantitative survey and a qualitative survey on drug use among Parisian adolescents. This research highlights the value of situating the observation of psychoactive substance use within its social context and will help to reframe the questions asked in questionnaire-based surveys and encourage the incorporation of new factors into the implementation of prevention policies.