The Marihuana Perception Inventory: the effects of substance abuse instruction

This article reports the latest results of a continuing effort to develop a perceptual inventory of factors associated with the onset of marihuana use among youths and young people. In addition to better understanding why adolescents begin using marihuana, the inventory is intended to assist drug educators target their programs. This phase studied 617 students in three Midwest school districts prior to and after substance abuse instruction to determine the relationship between perceptions and demographic characteristics, and to learn if substance abuse instruction was related to changes in the student's perception of the relationships. Factor analysis again revealed a five-factor solution. All thirty-four inventory items were included in the final solution. Items appeared to group themselves among the scales in a fashion similar to that found in prior studies. However, the larger sample size permitted refinement of the scales: Maturational Difficulties; Excessive Pressure; Parental Failings; Rebelliousness; and Societal/Institutional Weaknesses. The inventory appears to be remarkably stable across demographic characteristics. Significant differences between pretest and posttest scores indicated that students perceived less of a relationship between Maturational Difficulties, Excessive Pressure, and Societal/Institutional Weaknesses and the onset of marihuana use after instruction, and more of a relationship between Parental Failings and the young person's decision to begin using marihuana. It appears that instructional programs can be expected to at least contribute to changes in perceptions concerning the relationship between societal and familial factors and the onset of marihuana use.