TABLE 1

Means and Proportions of Sample Characteristics in 12th Grade (SEs in Parentheses)

VariableMean/Proportion
Legitimate use of opioids by 12th grade
 Question: “Have you ever taken any narcotics other than heroin because a doctor told you to use them?” Note: This variable is coded 1 for the response category “Yes, and it was the first time I took any.” Accompanying this question is a list of example drugs that has been updated over time and currently includes methadone, opium, morphine, Vicodin, MS Contin, codeine, Demerol, Roxycodone, hydrocodone (Lortab, Lorcet, Norco), Suboxone, OxyContin, Percocet, Tylox, Percodan, Ultram, and tramadol.0.15 (0.0048)
Lifetime marijuana use by 12th grade
 Question: “On how many occasions (if any) have you used marijuana?”
 None0.62 (0.0064)
 1–20.092 (0.0040)
 3–50.059 (0.0032)
 6–90.043 (0.0028)
 10–190.049 (0.0029)
 20–390.040 (0.0026)
 40+0.098 (0.0034)
Cigarette smoking history by 12th grade
 Question: “Have you ever smoked cigarettes?”
 Never0.48 (0.0067)
 Once or twice0.22 (0.0056)
 Occasionally but not regularly0.14 (0.0046)
 Regularly in the past0.05 (0.0030)
 Regularly now0.11 (0.0039)
Lifetime opioid use by 12th grade
 Question: “On how many occasions (if any) have you taken narcotics other than heroin on your own; that is, without a doctor telling you to take them?” Note: question includes an extensive list of example prescription opioids that is updated from year to year.
 None0.91 (0.0035)
 1–20.041 (0.0025)
 3–50.018 (0.0016)
 6–90.010 (0.0012)
 10–190.010 (0.0011)
 20–390.005 (0.0008)
 40+0.006 (0.0008)
Lifetime use of barbiturates and sedatives by 12th grade
 Question: “On how many occasions (if any) have you taken sedatives on your own; that is, without a doctor telling you to take them?” Note: question includes an extensive list of example prescription barbiturates and sedatives that is updated from year to year.
 None0.96 (0.0023)
 1–20.018 (0.0016)
 3–50.008 (0.0010)
 6–90.006 (0.0008)
 10–190.0037 (0.0006)
 20–390.0025 (0.0004)
 40+0.0035 (0.0005)
Binge drinking in past 2 wk at baseline, 12th grade survey
 Question: “During the last 2 weeks, how many times (if any) have you had 5 or more drinks in a row?”
 None0.79 (0.0054)
 Once0.085 (0.0037)
 Twice0.056 (0.0030)
 3–50.055 (0.0029)
 6–90.012 (0.0013)
 10+0.007 (0.0010)
Disapproval of regular marijuana use in 12th grade
 Question: “Do you disapprove of people (who are 18 or older) smoking marijuana regularly?”
 Don’t disapprove0.18 (0.0053)
 Disapprove0.26 (0.0064)
 Strongly disapprove0.55 (0.0070)
Women0.57 (0.0066)
Average course marks in 12th grade2.42 (0.025)
 Question: “Which of the following best describes your average grade so far in high school?” Values range from 9 for a “D” (69 or below) to 1 for an “A” (93–100).
Parent with college degree0.52 (0.0067)
 Coded 1 for respondents with either a mother or father with a college degree and 0 otherwise
Racial/ethnic minority0.27 (0.0060)
 Coded 0 for respondents who are non-Hispanic white and 1 otherwise