[Risk and protective factors in adolescents' drug use, and differences by age and sex].

Adolescents' drug use has huge social and personal implications, so it is essential to identify risk and protective factors. In this research, the CTCYS was used with 2440 adolescents to detect risk and protective factors for drug use in the community, family, school and peers/individual; differences in risk and protective factors by age and sex; and relationships between risk and protective factors and substance use. Protective factors are high. Risk factors are high in the community, the school and the individual. Older adolescents have more risks and less protection than the youngest; and there are sex differences, because males have less protection and more risks. The risk factors more closely related to drug use are availability of drugs in the community, family attitudes favourable to drug use, family history of antisocial behaviour, early start and use of drugs by friends, perceived risk and attitudes favourable to drug use. In the protective factors, the role played by social skills for alcohol use is important.