Gender Differences in the Longitudinal Development of Normative Beliefs for Tobacco, Alcohol and Marijuana Use Among Middle and High School Students

Over the past three decades, the field of prevention science has successfully developed interventions that are theoretically based. Evaluations of these interventions have identified normative beliefs regarding the use of substances among peers as a key mediating variable which is strongly and positively associated with adolescent substance use (e.g., Botvin et al., 2001). Studies using more than two assessments of normative beliefs are scarce (Lillehoj, 2005) and consequently less information is available about inter-individual differences in intra-individual change with respect to normative beliefs.

This study uses data from the Adolescent Substance Abuse Prevention Study. In this presentation, the focus is on students who were 12-13 years of age and who were in the control condition and who did not have missing data on the covariates of interest.  Of the 4411 students, 43.8% were male and 32.2% had used at least one of the three substances (alcohol, nicotine, marijuana) at baseline. Data were collected using self-administered surveys over the five-year study period: at baseline, about 30 to 60 days after baseline, approximately one year after the post-intervention survey when students were in 8^th grade, prior to the 9^th grade intervention, then again about 30 to 60 days after the 9^th grade pre-test survey, and approximately one and two years after the 9^th grade post-intervention survey, i.e., in 10^th and 11^thgrades. Normative beliefs were measured by assessing student’s ‟ perceptions of rates of use for each substance by students their age. Gender specific sequential General Growth Mixture Models for ordinal outcomes will be estimated to characterize developmental patterns in normative beliefs as well as developmental transitions between middle and high school.

For both genders, three developmental profiles during middle and high school were supported by the data, i.e., lower-, medium- and high levels of normative beliefs about tobacco use (Note: Results for alcohol and marijuana will be presented at the conference, but are omitted here for brevity) . During middle school females were more likely than males to perceive cigarette use as medium to highly normative (68.7% versus 58.6%). During high school these differences were less pronounced (Female: 74.4%; Male: 79.8%). With respect to transitions, females were more likely than males to remain in the high (82.9% versus 70.7%) and the low profile (72.5% versus 64.2%). In comparison, males were more likely than females to remain in the medium group (80.6% versus 71.5%)

The consistent evidence for inter individual differences in intra-individual change has the following implication: First, substance use prevention programming is implemented in a substance specific fashion and this study can assess whether and when students generalize across tobacco, alcohol and marijuana. Second, while there was little evidence for gender differences, the replication analysis for alcohol and marijuana will provide further evidence. The findings of aim 1 & 2 might support further refinement of substance use prevention curricula which account for these differences by implementing gender specific lessons.