Background
Rates of young adult cannabis use are rising, perceived harm is at
its historical nadir, and most users do not want to quit. Most studies
evaluating effects of cannabis use in young adults are cross-sectional,
limiting causal inference. A method to reliably induce abstinence periods in
cannabis users would allow assessment of the effects of abstinence and
resumption of use on a variety of outcomes in a within subjects, repeated
measure design.
Methods
We examined the efficacy and feasibility of a voucher-based
contingency management procedure for incentivizing one month of continuous
cannabis abstinence among young adults who reported at least weekly cannabis
use, volunteered to participate in a laboratory study, and did not express
desire to discontinue cannabis use long-term. Continuous cannabis abstinence
was reinforced with an escalating incentive schedule, and self-report of
abstinence was confirmed by frequent quantitative assays of urine cannabis
metabolite (THCCOOH) concentration. New cannabis use during the abstinence
period was determined using an established algorithm of change in
creatinine-adjusted cannabis metabolite concentration between study
visits.
Results
Thirty-eight young adults, aged 18–25, enrolled and 34
(89.5%) attained biochemically confirmed 30-day abstinence. Among
those who attained abstinence, 93.9% resumed regular use within
two-weeks of incentive discontinuation.
Conclusion
Findings support the feasibility and efficacy of contingency
management to elicit short-term, continuous cannabis abstinence among young
adult, non-treatment-seeking, regular cannabis users. Further work should
test the effectiveness of this CM procedure for cannabis abstinence periods
longer than one month, which may be required to evaluate some effects of
abstinence.