Cannabis use among adolescents and young adults poses significant risks to physical, cognitive, and psychosocial development, making it a crucial public health concern. The increasing availability and social acceptance of cannabis have contributed to its widespread use among youth, raising concerns about potential adverse outcomes associated with cannabis use, including increased vulnerability to psychiatric illness and substance dependence later in life. While abstinence is the safest option, it is imperative that we identify and develop interventions that reduce harm in youth who are not motivated to change their cannabis use. A recent study from researchers at the Center for Addiction Medicine at Mass General indicates that contingency management (CM) may be a promising strategy for mitigating cannabis use among non-treatment seeking youth.
This study was designed to assess the impact of contingency management (CM) on cannabis use attitudes and behaviors among non-treatment seeking youth. CM is a behavioral therapy approach that utilizes positive reinforcement to encourage and maintain desired behaviors.
A total of 220 youth (between the ages of 13 and 25) were randomized into either the CM-Abstinence group, which received abstinence-based CM, or the control group, which received monitoring but no CM intervention. Participants in the CM group were asked to immediately stop cannabis use. Throughout the 4-week intervention period, participants in the CM group were reimbursed during the intervention period using a two-track incentive system; they received payments (in the form of a debit card) for attendance, as well as escalating payments for biochemically-verified continuous cannabis abstinence. Those in the control group were paid on an escalating schedule for attendance. Additionally, in the CM group, participants were encouraged to set specific cannabis use reduction goals at the conclusion of the intervention, enabling the researchers to examine the impact of goal-setting on subsequent behavior change.
Data regarding the frequency of cannabis use and exposure levels were collected using a combination of self-report and biochemical assays quantifying THC metabolites in urine samples. Assessments were conducted at multiple time points, including at baseline, end-of-intervention, and at 4 weeks follow-up, in order to analyze behavior changes over time.
Of participants randomized to the CM intervention (n=126), 81.7% (n=103) had 4 weeks of biochemically-verified continuous cannabis abstinence. Compared to the control group, those in the CM group reported a greater decrease in frequency of cannabis use from baseline to follow-up at 4 weeks post-intervention.
Setting a reduction goal at the end of the CM intervention was associated with less cannabis use at follow-up (4 weeks post-intervention). Furthermore, individuals within the CM group who set specific reduction goals exhibited greater decreases in cannabis use frequency. This was most evident among those without a diagnosis of cannabis use disorder.
Participants in the CM group who resumed cannabis use during the intervention, withdrew consent, or were lost to follow up (n=23) were younger , had higher scores on the Cannabis Use Disorders Identification Test (CUDIT), used cannabis more frequently at baseline, and had higher urineTHC metabolite levels at baseline than CM participants who remained abstinent.
Contingency Management and Harm Reduction
Harm reduction strategies have gained traction as pragmatic approaches to mitigate the negative consequences of cannabis use among youth. By focusing on minimizing harm rather than promoting abstinence outright, harm reduction initiatives aim to engage youth in interventions that promote safer behaviors, empower informed decision-making, and ultimately reduce the overall burden of cannabis-related harm in this vulnerable population.
Overall, the current study provides robust evidence supporting the efficacy of contingency management as a harm reduction strategy for youth who may not yet be motivated to quit cannabis use entirely. Reductions in cannabis use were more pronounced in the CM group compared to the control group. Importantly, a substantial proportion of participants in the CM group expressed a continued desire to reduce or abstain from cannabis use even after the conclusion of the CM intervention, highlighting the sustained motivational effects of the intervention.
One of the criticisms of CM interventions is that they rely on tangible contingencies (money) and that behavioral changes elicited in this manner are short-lived. The findings of this study do not support this notion. In fact, more than two thirds of the participants set a goal of reducing their cannabis use after just 4 weeks of incentivized abstinence, despite reporting no interest in decreasing their use at the outset of the study. Furthermore, after this brief CM intervention, participants resumed use at a lower frequency than before the intervention. The authors note that this short-term period of CM may provide a window of time for self-reflection and motivation to change behavior even among people who were previously not interested in reducing their use of cannabis.
By harnessing the principles of positive reinforcement and goal-setting, CM offers a promising approach to promoting behavior change and reducing cannabis-related harm in adolescents and young adults. Further research and implementation efforts are warranted in order to optimize the effectiveness and scalability of CM interventions to address substance use among youth.
This publication was made possible by support from NIH-NIDA. Researchers contributing to this project included Megan E. Cooke, Sarah J. Knoll, Joanna Streck, Kevin Potter, Erin Lamberth, Natali Rychik, Jodi M. Gilman, A. Eden Evins, and Randi M. Schuster.
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Cooke ME, Knoll SJ, Streck JM, Potter K, Lamberth E, Rychik N, Gilman JM, Evins AE, Schuster RM. Contingency management is associated with positive changes in attitudes and reductions in cannabis use even after discontinuation of incentives among non-treatment seeking youth. Drug Alcohol Depend. 2024 Jan 20; 256:111096.
