The use of psychoactive substances and addictive behaviors are at the heart of current public health challenges, ranking among the behaviors that have a significant impact on morbidity and mortality rates in the population. On these issues, it is crucial that decision-making be based on scientific evidence and data representative of the entire population. This book is structured around an in-depth analysis of the results of the Health Barometer, a general population survey conducted by INPES since the early 1990s, with the most recent edition taking place in 2010. The survey examines the use of alcohol, tobacco, illicit drugs, psychotropic medications, poly-substance use, as well as gambling and betting. The large sample size (over 27,000 people) provides high precision in observing and tracking trends and allows for a certain level of detail in the analyses, making it possible, in particular, to clearly distinguish behaviors that fall under experimentation and occasional use from those—more rare—that pose a health or social risk, whether in the short or long term. This statistical power also makes it possible to track trends by occupational, economic, social, or demographic context—perspectives that are particularly useful for measuring trends in health inequalities. This book is intended for all those—citizens, policymakers, organizations, researchers, and others—who wish to gain a deeper understanding of the reality of addictive behaviors in France.