The schools and students were both randomly selected. The students completed the self-report questionnaires during the 1991-92 school term. The questionnaires collected information the use of nonmedical and medical drugs and alcohol and on gender, age, occupation during the previous year, study and work, and residence. Results revealed two major sources of variability. The first related to antisocial acts with severe social consequences, in which violence and drug selling were includes; the second related to thefts. Results also revealed significant differences in the number of offenses among groups of different gender, age, and occupation during the previous year. In addition, users of alcohol and drugs perpetrated more antisocial acts than did non users. A logistic regression model revealed that the main risk factors for perpetrating antisocial acts were being male, using alcohol, and using other drugs. Findings indicated that the Antisocial Behavior Scale has an adequate level of reliability and validity. Findings also indicated the need to develop programs to help teachers and other adults who are responsible for preventing antisocial behavior and drug consumption. Tables, appended questionnaire, author photographs and biographies, and 13 references (Author abstract modified)