Since 1999, the OFDT has been quantifying the opinions and perceptions of the French population on drugs and related public policies through the EROPP survey (Survey on representations, opinions and perceptions regarding psychoactive drugs). For this fifth edition, a sample of 2 001 individuals, representing the French population aged 18 to 75, was selected based on quota sampling. The survey makes it possible to see how opinions are structured around issues in the public debate but also to consider how opinions in France have developed over the last twenty years. For continuity, most of the themes studied in previous surveys have been kept (for example, the perceived dangerousness of different psychoactive substances, the representation of heroin users and opinions on drug legislation). In addition, questions on current topics and new issues have been added. In 2018, the EROPP survey focused on five psychoactive substances: tobacco, alcohol, cannabis, cocaine and heroin. Tendances No. 131 first discusses drug-related knowledge and how dangerous they are perceived to be. Secondly, it reports on individuals' adherence to public policies that are currently in force or being discussed in France or in other countries. Finally, a final section summarises cannabis users' opinions through a classification that groups together individuals with similar views. Where possible, the results are compared with those from previous surveys.