Young mothers’ decisions to use marijuana: A test of an expanded theory of planned behaviour

Abstract

The current study examines the Theory of Planned Behaviour's (TPB) ability to predict marijuana use among young women who experienced a premarital pregnancy before the age of 18 years, using longitudinal data. The validity of the TPB assumption that all other variables work through TPB constructs is also tested. Indicators of four constructs that have been shown in the literature to be predictive of marijuana use–persistent environmental adversity, emotional distress, adolescent marijuana use and drug use in the social network–were tested as predictors of attitudes, norms and self-efficacy, in a structural equation modelling framework. All paths from distal predictors were through the mediating TPB constructs, in accordance with the tenets of the model. Implications of these findings for the TPB model and for understanding factors that lead to marijuana use are discussed.

Keywords:

• theory of planned behaviour
• adolescents
• marijuana use
• decision-making

Acknowledgement

This research was supported by a grant from the National Institute on Drug Abuse (DA05208).

Notes

Note

1. In addition to the two respondents who died prior to the final data collection point, seven formally dropped out and eight others did not complete the final interview. Because a reasonable person might question whether the inclusion of these lost respondents changed the results, analyses were also run using the subset of respondents who completed the final wave of data collection (n = 223), to confirm that including those respondents did not substantively change the results. The only difference between the analyses was that two paths from environmental adversity that were marginally significant in analyses using the full sample became very slightly larger and significant while using the reduced sample.