Mortality resulting from alcohol abuse in young French people is too high in spite of prevention campaigns for road safety in particular. There are problems in identifying alcohol abuse in young people in preventive medicine or alcohol care services. This study was carried out in alcohol centres; data from patients under 25 are analysed and compared to a same-age group of young adults who are consulting in preventive medicine centres. In comparison with older people, these two groups of young adults presented similar characteristics, a lower educational grade, a precocity of psychotropic substance consumption, a preference for beers and spirits consumed episodically or during weekends, more frequent use of tobacco and cannabis, and, finally, greater frequency of drunkenness. The consequent risks of accidents are higher, on road use particularly. Therefore, early identification of alcohol abuse and training for professionals who work in socioeducational settings should be developed to improve the response to these new behaviours. The preventive medicine centres are appropriate for the detection of risk behaviours associated with alcohol or with polysubstance use. Local programs should be set up not only to delay the age of the first intake but to decrease the consumption peak.