Testing an expanded theory of planned behavior model to explain marijuana use among emerging adults in a promarijuana community.

Abstract

Opinions about marijuana use within the US are becoming increasingly favorable, making it important to understand how psychosocial influences impact individuals’ use within this context. Here we use the Theory of Planned Behavior (TPB) to examine the influence of initial attitudes, norms, and efficacy to resist use on initial intentions, and then the effect of initial intentions on actual marijuana use measured one year later using data drawn from a community with relatively high use. We expanded the traditional TPB model by investigating two types of normative influence (descriptive and injunctive) and two types of intentions (use intentions and proximity intentions), reasoning that exposure to high use in the population may produce high descriptive norms and proximity intentions overall, but not necessarily increase actual use. By contrast, we expected greater variability in injunctive norms and use intentions and that only use intentions would predict actual use. Consistent with hypotheses, intentions to use marijuana were predicted by injunctive norms (and attitudes) and in turn predicted marijuana use one year later. By contrast, descriptive norms were relatively high among all participants and did not predict intentions. Moreover, proximity intentions were not predictive of actual use. We also found that increasing intentions to use over a one year period predicted greater use. Given the greater efficacy of theory-based as compared to non-theory-based interventions, these findings provide critical information for the design of successful interventions to decrease marijuana-associated harms.

Extension of the Theory of Planned Behavior (TPB) to Predict Patterns of Marijuana Use among Young Iranian Adults

“…It follows that the individuals who had self-admitted themselves to a daycare center for substance use disorders to treat marijuana use should be instructed and reinforced in building-up strategies to resist marijuana use. Such strategies should include information about the negative long-term effects of marijuana [2,6,[12][13][14]33,[40][41][42], along with an explanation of the concept of self-control. Following cognitive-behavioral concepts [43], self-control is considered a specific behavior in a specific context which contains conflicting short-term and long-term outcomes.…”

“…To this end, in the present study we applied the Theory of Planned Behavior (TPB) [29,30] for the following reasons. Firstly, this theory has already been successfully used to identify predictors of marijuana use among adolescents and young adults (see [31][32][33]). This theoretical model has thus proved to be applicable in explaining marijuana use on the behavioral level and in supporting specific psychotherapeutic interventions.…”

Using the Confidence Interval-Based Estimation of Relevance Approach to Identify Determinants of Cannabis Use among High School Students in the Netherlands

“…Previous studies showed that the Theory of Planned Behaviour (TPB) can be useful in predicting intention and cannabis use (Malmberg et al, 2011;Ito, Henry, Cordova & Bryan, 2015). Intention is described as the strongest predictor of behaviour (Ajzen, 1985).…”

Applying Ajzen’s Theory of Planned Behaviour: Changing Physical Activity Health Behaviour with Activity-Tracking Technology

“…One of the most common and highly cited is the Theory of Planned Behaviour, which has been supported in many studies through a wide spectrum of experimental applications including the prediction of behaviours related to drug usage 27 , gambling 28 , and sexual behaviours 29 . However, it is in the domain of physical activity that the model has been extensively applied 30,31 .…”