[From tobacco use to other drugs use: does the early use of tobacco increase the probability of use of other drugs].

OBJECTIVE: To assess the likelihood of substance abuse predicted by age of first exposure to tobacco. MATERIAL AND METHODS: Data from the 1998 National Household Survey on Addictions in urban areas were analyzed. RESULTS: The age period of greater likelihood of drug experimentation is between 15 and 19 years; only 5.6% of drug users and 13% of alcohol beverage drinkers reported having experimented with drugs before trying tobacco. The probability of heavy drinking and dependence was higher at early ages of first exposure to tobacco and decreased with increasing age. Experimentation with drugs, continued use, and multiple drug use, are more frequent among smokers who started before 15 years of age. CONCLUSIONS: Early tobacco use increases the likelihood of substance abuse.