Intentions to use drugs among adolescents: a longitudinal analysis.

Data on the actual and intended use of psychoactive substances were used to predict substance use 1 year later for 1,177 adolescents. A confirmatory methodology tested whether the information contained in intentions to use drugs provided a sufficient increment over behavioral data in predicting future drug use. While the increment was statistically significant, the strength of the additional information was minimal. The results are interpreted as showing that little variance in adolescent substance use can be attributed to long-term cognitively purposeful behavior unique from previous drug-taking experience.