liquor (eg, vodka, gin, whiskey, and mixed drinks). First regular use of alcohol was defined as the age at which the respondent first had at least 12 drinks within a single year. For illicit drugs, participants were asked their age at which they had first (if ever) consumed a range of specific substances, including marijuana or hashish; cocaine in any form (eg, powder, crack, freebase, coca leaves, or paste); tranquilizers, stimulants, pain killers, or other prescription drugs either without the recommendation of a health professional or for any reason other than a health professional said they should be used; and heroin, opium, glue, lysergic acid diethylamide, peyote, or any other drug. Participants were also asked about the first time they had an opportunity to drink alcohol or use drugs, regardless of whether they used them. Opportunity to use was defined as when someone either offered them alcohol or drugs or when the individual was present when others were using and could have used if he or she wanted to. The age at first opportunity to use substances was recorded separately for alcohol and drugs. In light of the high availability of legal substances, such as alcohol, only opportunity to use
