Testing the Amotivational Syndrome: Marijuana Use Longitudinally Predicts Lower Self-Efficacy Even After Controlling for Demographics, Personality, and Alcohol and Cigarette Use

Abstract

The marijuana amotivational syndrome posits that cannabis use fosters apathy through the depletion of motivation-based constructs such as self-efficacy. The current study pursued a two-round design to rule out concomitant risk factors responsible for the connection from marijuana intake to lower general self-efficacy. College students (N = 505) completed measures of marijuana use, demographics (age, gender, and race), personality (extraversion, agreeableness, conscientiousness, openness, and neuroticism), other substance use (alcohol and tobacco), and general self-efficacy (initiative, effort, and persistence) in two assessments separated by a month. Hierarchical regression models found that marijuana use forecasted lower initiative and persistence, even after statistically ruling out 13 pertinent baseline covariates including demographics, personality traits, alcohol use, tobacco use, and self-efficacy subscales. A cross-lagged panel model involving initiative, effort, persistence, alcohol use, cigarette use, and marijuana use sought to unravel the temporal precedence of processes. Results showed that only marijuana (but not alcohol or tobacco) intake significantly and longitudinally prompted lower initiative and persistence. Furthermore, in the same model, the opposite temporal direction of events from lower general self-efficacy subscales to marijuana use was untenable. Findings provide partial support for the marijuana amotivational syndrome, underscore marijuana as a risk factor for decreased general self-efficacy, and offer implications and insights for marijuana prevention and future research.

Keywords: Amotivational syndrome; Cross-lagged panel modeling; General self-efficacy; Longitudinal; Marijuana.

Figure 1

Self-efficacy subscales as a function of T1 marijuana status (adjusted means and standard errors controlling for the same covariates in Table 1).

Figure 2

Cross-lagged panel model. All possible combinations of correlations involving T1 measures, as well as test-retest and cross-lagged paths from T1 to T2, are controlled in the model. For diagrammatic clarity, only significant (p < .05) coefficients are displayed. Coefficients to T2 initiative, effort, and persistence represent (adjusted) beta weights. Coefficients to T2 alcohol, cigarettes, and marijuana represented (adjusted) odds ratios. E = predictive error.