We investigated the percentage of individuals who progressed beyond first substance use. Because of slight differences in the assessment of substance use across cohorts, we only evaluated experimentation in Cohort II. In Cohort II, 69.5% of lifetime tobacco users reported having smoked cigarettes more than “one or two times ‘just to try’”; 93.1% of lifetime alcohol users reported having become regular drinkers (drinking at least once a month for six months or more) and/or having gotten drunk after their first experience with alcohol; and 79.4% of lifetime cannabis users reported having used cannabis three or more times. Therefore, it appears that for the majority of participants, age at first use was not one-time experimentation.
