Longitudinal examination of coping-motivated marijuana use and problematic outcomes among emerging adults.

ABSTRACT

OBJECTIVE: Cross-sectional research shows that coping-motivated marijuana use is associated with marijuana use and problems. However, limited research has examined how coping-motivated use might longitudinally relate to these outcomes. We examined the temporal relationship of coping-motivated marijuana use with severity of use and marijuana-related problems. METHOD: Participants were 226 emerging adults, aged 18-25 years old, who currently used marijuana. Multilevel generalized linear models were used to evaluate the association between change in coping motives with change in frequency of marijuana use and marijuana problem severity from baseline to 6- and 12-month follow-ups. RESULTS: In the adjusted models, frequency of marijuana use was positively associated with between subject differences (IRR = 1.49; 95%CI 1.30, 1.71; p < .001) but not within subject change over time (IRR = 1.09; 95%CI 0.97, 1.22; p = .139) in use of marijuana to cope. Additionally, marijuana problem severity scores were associated positively with between subject differences (IRR = 1.45; 95%CI 1.21, 1.75; p < .001) and within subject changes over time (IRR = 1.30; 95%CI 1.07, 1.57; p < .01) in use of marijuana to cope. CONCLUSIONS: Changes in coping-motivated use of marijuana in emerging adults were directionally associated with changes in marijuana use and marijuana problems up to 12 months post-baseline. Results highlight the possible bi-directional relationship between coping motives and marijuana use and problems. Findings could be valuable in helping practitioners go beyond quantity and frequency as sufficient metrics of marijuana use problems. Motives for use may reflect additional problems and the clinical need to explore these possibilities.