Data were taken from the National Household Survey on Drug Abuse. Respondents, age 12 or older, were asked to report the use of alcohol, cigarettes, or any illicit drug during the month prior to the survey. Illicit drugs refer to marijuana/hashish, cocaine (including crack), inhalants, hallucinogens, heroin, or prescription-type drugs used non-medically. They were also asked about their average grades in school for the last semester or grading period completed, and their participation in youth activities during the past year. Results of the survey show that youth that received grades of D or below were more likely than those with higher grades to have used cigarettes, alcohol, or illicit drugs during the past month. Youths with an A or B average were more likely to have used alcohol than other substances during the past month. Youths with a D or less than D average were more likely to have used cigarettes than other substances during this time period. The likelihood of participating in two or more youth activities was highest for youths with an A average and lowest for youths with a D or less than D average. Youths that participated in one or fewer youth activities in the past year were twice as likely to have used an illicit drug in the past month compared with youths that participated in two or more youth activities. 4 figures, 1 table, 3 endnotes