Applying an Extended Version of the Theory of Planned Behavior to Illicit Drug Use Among Students1
Journal of Applied Social Psychology August 1, 2003 Brian Mcmillan, Mark Conner 163 citations
The theory of planned behavior (TPB) predicted intentions to use and actual use of LSD, amphetamine, cannabis, and ecstasy over six months among 461 students. The TPB explained about 49% of the variance in intentions and 45% in behavior. Descriptive norms added to the prediction of intentions for all four drugs, while moral norms further predicted cannabis intentions. Attitude variability weakened or strengthened the link between attitudes and intentions for LSD and ecstasy. Attitudes also influenced how strongly perceived behavioral control affected intentions for all drugs. Perceived behavioral control moderated the intention-behavior link for each drug, showing that the TPB's relationships depend on other factors.