Applying an Extended Version of the Theory of Planned Behavior to Illicit Drug Use Among Students1
Journal of Applied Social Psychology August 1, 2003 DOI: 10.1111/j.1559-1816.2003.tb01968.x (opens in new tab)
Study at a glance
AI-extracted from the abstract| Characteristics | Observational cohort Peer reviewed |
|---|---|
| Sample size | 461 |
| Population | Students |
| Duration | 6-month follow-up |
| Keywords | Illicit drug |
| Citations | 163 |
| Key findings | The theory of planned behavior predicted intentions and use of four illicit drugs over six months, with descriptive norms, moral norms, and interactions among attitudes, perceived behavioral control, and intentions revealing boundary conditions. |
Abstract
This study employed the theory of planned behavior (TPB) to investigate the factors underlying intentions to use and use of LSD, amphetamine, cannabis, and ecstasy over 6 months in a sample of students ( N = 461). The TPB provided good predictions of both intentions (mean R 2 = .49) and behavior (mean R 2 = .45). Descriptive norms explained additional variance in intentions for all the drugs, and moral norms explained additional variance in cannabis intentions. Attitude variability moderated the impact of attitudes on intentions for LSD ( p < .10) and ecstasy ( p < .05). Attitude moderated the impact of perceived behavioral control (PBC) on intentions for all drugs ( p < .001). PBC moderated the impact of intentions on behavior for LSD ( p < .05), amphetamine ( p < .10), cannabis ( p < .05), and ecstasy ( p < .10). These interaction effects elucidate limiting conditions among the variables in the TPB.