A biopsychosocial examination of lifetime alcohol, tobacco, and other drug use among Indiana adolescents: Simultaneous assessment of substance use rate and severity

Objective. The purposes of this study were to: (1) identify Indiana middle and high school students' self-reported lifetime use patterns for 17 substances; and (2) examine sociodemographics, psychological factors, and normative beliefs associated with the rate and severity of students' lifetime substance use.

Methods. Data were collected using a cross-sectional survey of 1,233 Indiana 7th through 12th grade students. Theta scores were calculated from participant responses about lifetime drug use for 17 substances using 2PL item response theory modeling. Theta scores are standardized statistics simultaneously representing the number of substances each individual tried and the rate of use for each substance among the entire sample. General least squares regression was performed to examine how students' personal characteristics and latent Biopsychosocial Model constructs were associated with theta scores.

Results. Over 66% of students reported using one or more substance in their lifetime. Participants in higher grade levels (beta=0.27, P<0.001), those reporting worse worry control (beta=0.11, P<0.001), and those perceiving their parents (beta=0.13, P<0.001) and peers (beta=0.41, P<0.001) were more approving of substance use had significantly higher theta scores. Participants who perceived the risks of drug use outweighed the benefits (beta=-0.12, P<0.001) and conformed less to negative influences (beta=-0.07, P=0.015) had significantly lower theta scores.

Conclusion: Simultaneously investigating the frequency and deleteriousness of substances used among adolescents can identify gateway substances. Further, assessing the influences of psychological and normative factors on adolescent drug use may inform health professionals, school officials, and parents about effective strategies to prevent substance use initiation and progression.