[Risk factors for the consumption of illegal drugs. Study in 1904 18-year-old boys in the city of Buenos Aires].

During September 1988 an anonymous, self-administered survey was carried out among a random sample of 18-year-old boys living in Buenos Aires city. The characteristics of 232 boys who reported illegal drug usage during the previous year were compared against those of the 1672 who denied drug consumption during that period. Forward stepwise multiple logistic regression analysis showed strong association between drug use and drug consumption by friends (OR 18.6) or brother/sister (OR 4.3), and consumption of tobacco or alcohol (OR 4.5 and 4.2 respectively). Results show different characteristics that can facilitate the primary care physicians' task of prevention and diagnosis of drug consumption in his/her patients.