A Biopsychosocial Examination of ATOD Use among Middle and High School Students.

Objective: To examine Indiana middle and high school students' use of 17 licit and illicit substances using item response theory to produce theta scores to identify sociodemographics, psychological factors, and normative beliefs associated with life-time drug use.

Methods: Cross-sectional data from 1233 students were examined. Theta scores were calculated across 17 substances using 2PL item response theory modeling. General least squares regressions were performed.

Results: Those perceiving their peers/parents approved substance use and those reporting worse worry control had higher theta scores. Those perceiving the risks of drug use outweighed the benefits and conforming less to negative influences had significantly lower theta scores.

Conclusions: Findings support the utility of the Biopsychosocial Model to examine lifetime drug use and the severity of substances used among adolescents simultaneously.