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Self-efficacy to employ cognitive-behavioral strategies to reduce marijuana use among attendees at a marijuana festival in the Midwest Alan K. Davis, Stacey L. Bradbury, Nicole Cross, Harold Rosenberg, Kirstin J. Lauritsen, Brent Lang, Lisham Ashrafioun, Lawrence A. Osborn, Victoria Carhart, Kyoung doek-Baik Department of Psychology, Bowling Green State University, Bowling Green, OH, USA
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Alan Kooi Davis
The authors disclose no conflict of interest.
Introduction
More Results
Results
Almost one-third (31%) of Americans between the ages of 19 and 30 years old reported using marijuana during the previous year, and 18% reported using it within the previous 30 days.
Although most people who use marijuana will not develop a substance use disorder, some people consume marijuana so rapidly, so frequently, and in such large amounts that they experience biomedical and psychosocial consequences.
Some of these potentially harmful consequences could be avoided or reduced if users employed cognitive-behavioral self-control strategies to limit the frequency, amount, and/or speed with which they consume marijuana.
Using a sample recruited at an outdoor marijuana festival, we evaluated several psychometric properties of a questionnaire designed to assess self-efficacy to employ use-reduction strategies.
Reliability
Principal Components Analysis yielded two components with eigenvalues greater than 1.0; however, the second component had a relatively small eigenvalue (1.09) and accounted for relatively little additional variance (5.2%)
Cronbach’s alpha across all 21 items was excellent (α= . 97)
Mean inter-item correlation = . 62
We concluded that the 21 items comprised a single scale.
Analyses of Criterion Validity
Pearson product-moment correlations revealed that MJ-RS-SES scores were significantly negatively correlated with the number of days per week participants consumed marijuana (r = -.30), the number of marijuana use sessions per day (r = -.29), and the amount of marijuana consumed per session (r = -.27), all Ps < .001.
The 88 participants who reported that they were not intoxicated while completing study did not differ in their mean self-efficacy scores compared to the 221 who were intoxicated.
To follow-up this analysis, we evaluated whether subjective level of intoxication among the intoxicated participants was associated with their scores on the MJ-RS-SES. A Pearson product-moment correlation revealed no significant relation between subjective level of intoxication and MJ-RS-SES scores.
Figure 1 shows the results from the significant ANOVA evaluating the differences in MJ-RS-SES scores as a function of past reduction attempts. Figure 2 shows the results from the significant ANOVA evaluating the differences in MJ-RS-SES scores as a function of recent stability of marijuana use.
Procedure
Six teams of researchers approached an arbitrarily selected subset of the estimated 8,000 people who attended the 43rd annual Hash Bash festival in Ann Arbor, Michigan on April 5, 2014, to ask if they would participate in the current study.
Participants had to be at least 18 years of age.
All participants were offered a small bag of chips as compensation
After presenting potential participants with an informed consent sheet, answering questions they might have about the study, and obtaining verbal consent to participate (to preserve anonymity), we administered a paper-and-pencil version of the Marijuana-Reduction Strategies-Self-efficacy Scale (MJ-RS-SES) and Drug Use History and Demographics Questionnaires.
Participant Characteristics and MJ Use
368 individuals consented to participate in the study.
322 completed the MJ-RS-SES, met eligibility criteria, and were included in analyses.
Participants were young (Mage= 22.4, SD = 6.2); 66% were male, 80% were White/Caucasian, and 88% were heterosexual.
Marijuana use history:
Mean consumption = 5.8 days per week (SD = 1.9).
58% of participants had attempted to reduce their marijuana use between 1 or more times in their lifetime.
72% were intoxicated while filling out the questionnaires.
14% reported their use decreased, 61% reported their use stayed the same, and 25% reported their use increased, in the past 6 months.
Discussion
Similar to the first and second evaluation of this instrument, reliability analyses in the current sample supported retaining all 21 strategies as a single scale.
These findings support the psychometric properties of the questionnaire administered to young recreational marijuana users in a naturalistic setting.
Future research should evaluate the extent to which self-efficacy to reduce marijuana use predicts actual implementation of use-reduction strategies by recreational and problematic users in different contexts.
A longitudinal design with repeated measurement of strategy-specific use-reduction self-efficacy over the course of a year would provide a stronger evaluation of those who have recently reduced their consumption of marijuana, assuming that this group should have higher self-efficacy to employ these reduction strategies.