Young adults have the highest rates of cannabis use disorder but are the least likely to receive treatment. At the same time, their smartphone use is nearly universal. This study exploited this common use among young adults to test a text message-delivered intervention to reduce their cannabis use.
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Cannabis use disorder is most prevalent among young adults (ages 18-25), with 16.6% meeting criteria for the disorder. Yet, this age group is the least likely to receive treatment. Heavy cannabis use in young adulthood has been linked to a range of negative outcomes, including psychiatric symptoms, neurocognitive changes, and increased risk of motor vehicle accidents. These concerns are magnified by the shifting legal landscape of cannabis, which has increased the availability and marketing of cheap, high potency products, while contributing to declining perceptions of harm.
Young adults report a range of barriers to engaging in cannabis use treatment, including stigma, cost, doubts about treatment effectiveness, not being ready to quit cannabis use entirely, and a preference to self-manage their use. These challenges highlight a need for innovative, scalable interventions that meet the needs and preferences of young adults.
Nearly all young adults own a smartphone and check these devices frequently; on average, young adults send and receive 128 text messages per day, with most texts read within 5 minutes of receipt. Thus, delivering cannabis reduction support via text messaging offers a promising format that aligns with young adults’ communication preferences and may improve engagement.
In addition to testing whether a text message-delivered intervention can reduce cannabis use among young adults, understanding how exactly an intervention like this works can help inform and strengthen future interventions. Prior research has identified 3 potential mechanisms of change that explain how cannabis use disorder treatment works: 1) social (peer influences on cannabis use behaviors); 2) cognitive (readiness to change cannabis use behaviors); and 3) behavioral (use of protective behavioral strategies to reduce negative consequences of cannabis use). However, these mechanisms have not been examined within a fully text message-delivered intervention. This study evaluated whether a 4-week, text message-delivered cannabis reduction intervention designed to target peer influence, motivation to change, and harm reduction strategies could reduce cannabis use among young adults, and whether these mechanisms played a significant role in promoting changes in cannabis-related behaviors.
This study was a 2-arm parallel randomized controlled trial with 1078 young adults (ages 18-25) with likely cannabis use disorder based on a screener, positive toxicology screen for THC, and no recent substance use treatment. Participants were recruited from Colorado (551) and Tennessee (527) through geographically targeted social media ads and flyers posted on college campuses. After enrollment, participants were randomly assigned to either a 4-week text message-delivered intervention or a waitlist control group that only completed assessments, and were followed for 6 months. The sample was a little over half female (57%), mostly White (71%), and just over half (53%) currently enrolled in college.
The intervention was adapted from an in-person treatment known as Peer Network Counseling, which employs motivational interviewing principles to explore individuals’ personal goals, bolster motivation to change, and encourage reflection on peer influences (see graphic below). In the text messaged-based version, participants received 160 tailored text messages over 4 weeks, delivered every other day. The messages encouraged participants to consider how their social environment, particularly their closest friends, aligned with or conflicted with their health and life goals. The intervention also delivers content on protective behavioral strategies that can be used to reduce cannabis-related harms, such as only using cannabis on the weekends. Participants completed a baseline survey on their cannabis use, peer relationships, attitudes, goals, and plans for change. The information gathered in the survey was used to personalize the text message conversations, which were delivered through an automated platform. Participants could choose the time of day to receive their texts and had the option to request additional motivational, mental health, or harm reduction messages on demand.
Primary outcomes were self-reported cannabis use (past 30-day frequency) and THC metabolite levels measured by drug tests sent through the mail, assessed at 1, 3, and 6 months post-baseline. Secondary outcomes focused on 3 hypothesized mechanisms of change: 1) motivation to change, measured using the Marijuana Ladder; 2) use of protective behavioral strategies, assessed with the Protective Behavioral Strategies for Marijuana Scale; and 3) peer network health, measured by the Young Adult Social Network Assessment, which calculates the balance of participants’ perceptions of their closest peers’ protective (e.g., encouragement for non-cannabis use) versus risky behaviors (e.g., peer cannabis use)
For the analysis, researchers tested whether changes in cannabis use over time differed significantly between the treatment and control groups. They also conducted mediation analysis to examine whether the intervention influenced cannabis use indirectly, by first increasing motivation to change, improving peer-related factors, or promoting usage of protective behavioral strategies, which then led to reductions in cannabis use.
The text message-delivered intervention did not do better than waitlist control
The text-message delivered intervention did not significantly reduce cannabis use compared to the waitlist control group over the 6-month follow-up period (see graph below). However, both groups reported notable reductions of about 4 fewer days of past 30-day cannabis use from baseline to 6 months. At 6 months, participants in the treatment group reported an average of 21.9 days of past 30-day cannabis use, compared to 22.4 days in the control group.
The intervention improved motivation and use of harm reduction strategies, but not changes in peer networks
Compared to controls, the intervention group had greater increases in readiness to change their cannabis use at 1 and 3 months, and greater use of protective behavioral strategies at 1 month. However, the intervention and control groups had similar improvements in their peer network health (i.e., more protective than risk factors) over time.
Cannabis use was indirectly reduced through increased motivation and use of protective behavioral strategies
Although the intervention did not directly reduce cannabis use more compared to the control group, analyses focused on how the treatment worked (i.e., mediation analyses) revealed indirect effects. As mentioned above, the treatment increased motivation to change and use of protective behavioral strategies more than controls at 1 month, and the study also found that shifts in these variables predicted lower cannabis use at 6 months. Together, this suggests the intervention may work by activating these underlying mechanisms of change. Importantly, however, since the intervention and control had similar outcomes despite the intervention doing better on these potential mechanisms (e.g., readiness and protective behavioral strategies), there are likely many other important theoretical factors explaining how young adults modify their cannabis use over time.
Surprisingly, the text message-delivered intervention based on sound psychological and proven intervention principles did not outperform the waitlist control in directly reducing cannabis use over time. However, it did increase motivation to change and the use of protective behavioral strategies, 2 factors that were shown to predict reduced cannabis use at 6 months. That said, despite the treatment working as intended, the similar outcomes for intervention and control mean that there are many other theoretical factors explaining how young adults modify their cannabis use over time. Also of note, though peer influence is a well-established factor in substance use and recovery, and this intervention was designed to create positive shifts in peer networks, the intervention did not produce changes in peer network health, which may require more time or more intensive approaches to be impactful.
These findings are consistent with results from a prior pilot study by the same authors, which also tested the Peer Network Counseling text message-delivered intervention and found no direct effect on heavy cannabis use. Similarly, other digital interventions aimed at reducing cannabis use have failed to outperform controls that included education alone. One possible explanation is that the act of completing study assessments may have prompted self-directed behavior change – a phenomenon known as measurement reactivity, where the process of tracking behavior itself can lead to change. For example, social network improvements were similar between groups, suggesting the participants who did not receive the text message intervention also made changes that helped improve their cannabis use. This raises the question of whether the intervention offers added value beyond simple behavior tracking, especially when considering the additional cost and effort of delivering a structured program. However, text message-delivered and other digital interventions vary in their effectiveness. For example, a recent trial of a text message-delivered intervention in adults for reducing alcohol use showed significant improvements in drinking outcomes at 6 months, beyond what was achieved through drink tracking alone. Further research is needed to better understand why similar results have not been consistently observed for cannabis-focused digital interventions in young adults.
Regarding mechanisms of change, findings were mixed when compared to prior research. Earlier studies have supported 3 targeted mechanisms – positive shifts in one’s peer network, readiness to change, and protective behavioral strategies. This text message-delivered adaptation led to increases in motivation to change and use of protective behavioral strategies, but did not produce changes in peer network health. One important caveat is that the study was conducted during the COVID-19 pandemic, a period when limited social interaction may have reduced the influence of peers; though this would be expected to impact groups equally given the randomized design. Notably, the intervention increased readiness to change at 1 month compared to control, which was then associated with reduced cannabis use at 6 months. This finding is consistent with the motivational interviewing framework, which has strong empirical support for reducing substance use. Similarly, increased use of protective behavioral strategies was also linked to reduced cannabis use at 6 months. This aligns with prior research and may reflect a broader pattern among young adults who may be open to reducing cannabis-related harms without pursuing abstinence or in-person treatment. In this context, flexible and accessible digital intervention formats may be particularly well-suited to meet the needs of this population.
A brief, text message-delivered intervention did not reduce cannabis use more than a waitlist control, and was found to promote reductions indirectly by increasing motivation to change and encouraging the use of protective behavioral strategies. Given the widespread, daily use of smartphones among young adults, scalable and low-cost digital interventions may offer meaningful public health benefits, particularly for individuals who prefer to self-manage their cannabis use or are unwilling or unable to engage in traditional, in-person treatment. However, for young adults who are already motivated to change their cannabis use, simply tracking cannabis use over time may be just as effective as receiving a structured peer network counseling text message program. Future research is needed to explore how digital tools can be optimized or combined with other supports to enhance their effectiveness.
Mason, M. J., Coatsworth, J. D., Riggs, N. R., Russell, M., Mennis, J., Zaharakis, N., & Brown, A. (2025). Text message-delivered cannabis use disorder treatment with young adults: A large randomized clinical trial. Journal of Substance Use and Addiction Treatment, 170. doi: 10.1016/j.josat.2024.209611.
l
Cannabis use disorder is most prevalent among young adults (ages 18-25), with 16.6% meeting criteria for the disorder. Yet, this age group is the least likely to receive treatment. Heavy cannabis use in young adulthood has been linked to a range of negative outcomes, including psychiatric symptoms, neurocognitive changes, and increased risk of motor vehicle accidents. These concerns are magnified by the shifting legal landscape of cannabis, which has increased the availability and marketing of cheap, high potency products, while contributing to declining perceptions of harm.
Young adults report a range of barriers to engaging in cannabis use treatment, including stigma, cost, doubts about treatment effectiveness, not being ready to quit cannabis use entirely, and a preference to self-manage their use. These challenges highlight a need for innovative, scalable interventions that meet the needs and preferences of young adults.
Nearly all young adults own a smartphone and check these devices frequently; on average, young adults send and receive 128 text messages per day, with most texts read within 5 minutes of receipt. Thus, delivering cannabis reduction support via text messaging offers a promising format that aligns with young adults’ communication preferences and may improve engagement.
In addition to testing whether a text message-delivered intervention can reduce cannabis use among young adults, understanding how exactly an intervention like this works can help inform and strengthen future interventions. Prior research has identified 3 potential mechanisms of change that explain how cannabis use disorder treatment works: 1) social (peer influences on cannabis use behaviors); 2) cognitive (readiness to change cannabis use behaviors); and 3) behavioral (use of protective behavioral strategies to reduce negative consequences of cannabis use). However, these mechanisms have not been examined within a fully text message-delivered intervention. This study evaluated whether a 4-week, text message-delivered cannabis reduction intervention designed to target peer influence, motivation to change, and harm reduction strategies could reduce cannabis use among young adults, and whether these mechanisms played a significant role in promoting changes in cannabis-related behaviors.
This study was a 2-arm parallel randomized controlled trial with 1078 young adults (ages 18-25) with likely cannabis use disorder based on a screener, positive toxicology screen for THC, and no recent substance use treatment. Participants were recruited from Colorado (551) and Tennessee (527) through geographically targeted social media ads and flyers posted on college campuses. After enrollment, participants were randomly assigned to either a 4-week text message-delivered intervention or a waitlist control group that only completed assessments, and were followed for 6 months. The sample was a little over half female (57%), mostly White (71%), and just over half (53%) currently enrolled in college.
The intervention was adapted from an in-person treatment known as Peer Network Counseling, which employs motivational interviewing principles to explore individuals’ personal goals, bolster motivation to change, and encourage reflection on peer influences (see graphic below). In the text messaged-based version, participants received 160 tailored text messages over 4 weeks, delivered every other day. The messages encouraged participants to consider how their social environment, particularly their closest friends, aligned with or conflicted with their health and life goals. The intervention also delivers content on protective behavioral strategies that can be used to reduce cannabis-related harms, such as only using cannabis on the weekends. Participants completed a baseline survey on their cannabis use, peer relationships, attitudes, goals, and plans for change. The information gathered in the survey was used to personalize the text message conversations, which were delivered through an automated platform. Participants could choose the time of day to receive their texts and had the option to request additional motivational, mental health, or harm reduction messages on demand.
Primary outcomes were self-reported cannabis use (past 30-day frequency) and THC metabolite levels measured by drug tests sent through the mail, assessed at 1, 3, and 6 months post-baseline. Secondary outcomes focused on 3 hypothesized mechanisms of change: 1) motivation to change, measured using the Marijuana Ladder; 2) use of protective behavioral strategies, assessed with the Protective Behavioral Strategies for Marijuana Scale; and 3) peer network health, measured by the Young Adult Social Network Assessment, which calculates the balance of participants’ perceptions of their closest peers’ protective (e.g., encouragement for non-cannabis use) versus risky behaviors (e.g., peer cannabis use)
For the analysis, researchers tested whether changes in cannabis use over time differed significantly between the treatment and control groups. They also conducted mediation analysis to examine whether the intervention influenced cannabis use indirectly, by first increasing motivation to change, improving peer-related factors, or promoting usage of protective behavioral strategies, which then led to reductions in cannabis use.
The text message-delivered intervention did not do better than waitlist control
The text-message delivered intervention did not significantly reduce cannabis use compared to the waitlist control group over the 6-month follow-up period (see graph below). However, both groups reported notable reductions of about 4 fewer days of past 30-day cannabis use from baseline to 6 months. At 6 months, participants in the treatment group reported an average of 21.9 days of past 30-day cannabis use, compared to 22.4 days in the control group.
The intervention improved motivation and use of harm reduction strategies, but not changes in peer networks
Compared to controls, the intervention group had greater increases in readiness to change their cannabis use at 1 and 3 months, and greater use of protective behavioral strategies at 1 month. However, the intervention and control groups had similar improvements in their peer network health (i.e., more protective than risk factors) over time.
Cannabis use was indirectly reduced through increased motivation and use of protective behavioral strategies
Although the intervention did not directly reduce cannabis use more compared to the control group, analyses focused on how the treatment worked (i.e., mediation analyses) revealed indirect effects. As mentioned above, the treatment increased motivation to change and use of protective behavioral strategies more than controls at 1 month, and the study also found that shifts in these variables predicted lower cannabis use at 6 months. Together, this suggests the intervention may work by activating these underlying mechanisms of change. Importantly, however, since the intervention and control had similar outcomes despite the intervention doing better on these potential mechanisms (e.g., readiness and protective behavioral strategies), there are likely many other important theoretical factors explaining how young adults modify their cannabis use over time.
Surprisingly, the text message-delivered intervention based on sound psychological and proven intervention principles did not outperform the waitlist control in directly reducing cannabis use over time. However, it did increase motivation to change and the use of protective behavioral strategies, 2 factors that were shown to predict reduced cannabis use at 6 months. That said, despite the treatment working as intended, the similar outcomes for intervention and control mean that there are many other theoretical factors explaining how young adults modify their cannabis use over time. Also of note, though peer influence is a well-established factor in substance use and recovery, and this intervention was designed to create positive shifts in peer networks, the intervention did not produce changes in peer network health, which may require more time or more intensive approaches to be impactful.
These findings are consistent with results from a prior pilot study by the same authors, which also tested the Peer Network Counseling text message-delivered intervention and found no direct effect on heavy cannabis use. Similarly, other digital interventions aimed at reducing cannabis use have failed to outperform controls that included education alone. One possible explanation is that the act of completing study assessments may have prompted self-directed behavior change – a phenomenon known as measurement reactivity, where the process of tracking behavior itself can lead to change. For example, social network improvements were similar between groups, suggesting the participants who did not receive the text message intervention also made changes that helped improve their cannabis use. This raises the question of whether the intervention offers added value beyond simple behavior tracking, especially when considering the additional cost and effort of delivering a structured program. However, text message-delivered and other digital interventions vary in their effectiveness. For example, a recent trial of a text message-delivered intervention in adults for reducing alcohol use showed significant improvements in drinking outcomes at 6 months, beyond what was achieved through drink tracking alone. Further research is needed to better understand why similar results have not been consistently observed for cannabis-focused digital interventions in young adults.
Regarding mechanisms of change, findings were mixed when compared to prior research. Earlier studies have supported 3 targeted mechanisms – positive shifts in one’s peer network, readiness to change, and protective behavioral strategies. This text message-delivered adaptation led to increases in motivation to change and use of protective behavioral strategies, but did not produce changes in peer network health. One important caveat is that the study was conducted during the COVID-19 pandemic, a period when limited social interaction may have reduced the influence of peers; though this would be expected to impact groups equally given the randomized design. Notably, the intervention increased readiness to change at 1 month compared to control, which was then associated with reduced cannabis use at 6 months. This finding is consistent with the motivational interviewing framework, which has strong empirical support for reducing substance use. Similarly, increased use of protective behavioral strategies was also linked to reduced cannabis use at 6 months. This aligns with prior research and may reflect a broader pattern among young adults who may be open to reducing cannabis-related harms without pursuing abstinence or in-person treatment. In this context, flexible and accessible digital intervention formats may be particularly well-suited to meet the needs of this population.
A brief, text message-delivered intervention did not reduce cannabis use more than a waitlist control, and was found to promote reductions indirectly by increasing motivation to change and encouraging the use of protective behavioral strategies. Given the widespread, daily use of smartphones among young adults, scalable and low-cost digital interventions may offer meaningful public health benefits, particularly for individuals who prefer to self-manage their cannabis use or are unwilling or unable to engage in traditional, in-person treatment. However, for young adults who are already motivated to change their cannabis use, simply tracking cannabis use over time may be just as effective as receiving a structured peer network counseling text message program. Future research is needed to explore how digital tools can be optimized or combined with other supports to enhance their effectiveness.
Mason, M. J., Coatsworth, J. D., Riggs, N. R., Russell, M., Mennis, J., Zaharakis, N., & Brown, A. (2025). Text message-delivered cannabis use disorder treatment with young adults: A large randomized clinical trial. Journal of Substance Use and Addiction Treatment, 170. doi: 10.1016/j.josat.2024.209611.
l
Cannabis use disorder is most prevalent among young adults (ages 18-25), with 16.6% meeting criteria for the disorder. Yet, this age group is the least likely to receive treatment. Heavy cannabis use in young adulthood has been linked to a range of negative outcomes, including psychiatric symptoms, neurocognitive changes, and increased risk of motor vehicle accidents. These concerns are magnified by the shifting legal landscape of cannabis, which has increased the availability and marketing of cheap, high potency products, while contributing to declining perceptions of harm.
Young adults report a range of barriers to engaging in cannabis use treatment, including stigma, cost, doubts about treatment effectiveness, not being ready to quit cannabis use entirely, and a preference to self-manage their use. These challenges highlight a need for innovative, scalable interventions that meet the needs and preferences of young adults.
Nearly all young adults own a smartphone and check these devices frequently; on average, young adults send and receive 128 text messages per day, with most texts read within 5 minutes of receipt. Thus, delivering cannabis reduction support via text messaging offers a promising format that aligns with young adults’ communication preferences and may improve engagement.
In addition to testing whether a text message-delivered intervention can reduce cannabis use among young adults, understanding how exactly an intervention like this works can help inform and strengthen future interventions. Prior research has identified 3 potential mechanisms of change that explain how cannabis use disorder treatment works: 1) social (peer influences on cannabis use behaviors); 2) cognitive (readiness to change cannabis use behaviors); and 3) behavioral (use of protective behavioral strategies to reduce negative consequences of cannabis use). However, these mechanisms have not been examined within a fully text message-delivered intervention. This study evaluated whether a 4-week, text message-delivered cannabis reduction intervention designed to target peer influence, motivation to change, and harm reduction strategies could reduce cannabis use among young adults, and whether these mechanisms played a significant role in promoting changes in cannabis-related behaviors.
This study was a 2-arm parallel randomized controlled trial with 1078 young adults (ages 18-25) with likely cannabis use disorder based on a screener, positive toxicology screen for THC, and no recent substance use treatment. Participants were recruited from Colorado (551) and Tennessee (527) through geographically targeted social media ads and flyers posted on college campuses. After enrollment, participants were randomly assigned to either a 4-week text message-delivered intervention or a waitlist control group that only completed assessments, and were followed for 6 months. The sample was a little over half female (57%), mostly White (71%), and just over half (53%) currently enrolled in college.
The intervention was adapted from an in-person treatment known as Peer Network Counseling, which employs motivational interviewing principles to explore individuals’ personal goals, bolster motivation to change, and encourage reflection on peer influences (see graphic below). In the text messaged-based version, participants received 160 tailored text messages over 4 weeks, delivered every other day. The messages encouraged participants to consider how their social environment, particularly their closest friends, aligned with or conflicted with their health and life goals. The intervention also delivers content on protective behavioral strategies that can be used to reduce cannabis-related harms, such as only using cannabis on the weekends. Participants completed a baseline survey on their cannabis use, peer relationships, attitudes, goals, and plans for change. The information gathered in the survey was used to personalize the text message conversations, which were delivered through an automated platform. Participants could choose the time of day to receive their texts and had the option to request additional motivational, mental health, or harm reduction messages on demand.
Primary outcomes were self-reported cannabis use (past 30-day frequency) and THC metabolite levels measured by drug tests sent through the mail, assessed at 1, 3, and 6 months post-baseline. Secondary outcomes focused on 3 hypothesized mechanisms of change: 1) motivation to change, measured using the Marijuana Ladder; 2) use of protective behavioral strategies, assessed with the Protective Behavioral Strategies for Marijuana Scale; and 3) peer network health, measured by the Young Adult Social Network Assessment, which calculates the balance of participants’ perceptions of their closest peers’ protective (e.g., encouragement for non-cannabis use) versus risky behaviors (e.g., peer cannabis use)
For the analysis, researchers tested whether changes in cannabis use over time differed significantly between the treatment and control groups. They also conducted mediation analysis to examine whether the intervention influenced cannabis use indirectly, by first increasing motivation to change, improving peer-related factors, or promoting usage of protective behavioral strategies, which then led to reductions in cannabis use.
The text message-delivered intervention did not do better than waitlist control
The text-message delivered intervention did not significantly reduce cannabis use compared to the waitlist control group over the 6-month follow-up period (see graph below). However, both groups reported notable reductions of about 4 fewer days of past 30-day cannabis use from baseline to 6 months. At 6 months, participants in the treatment group reported an average of 21.9 days of past 30-day cannabis use, compared to 22.4 days in the control group.
The intervention improved motivation and use of harm reduction strategies, but not changes in peer networks
Compared to controls, the intervention group had greater increases in readiness to change their cannabis use at 1 and 3 months, and greater use of protective behavioral strategies at 1 month. However, the intervention and control groups had similar improvements in their peer network health (i.e., more protective than risk factors) over time.
Cannabis use was indirectly reduced through increased motivation and use of protective behavioral strategies
Although the intervention did not directly reduce cannabis use more compared to the control group, analyses focused on how the treatment worked (i.e., mediation analyses) revealed indirect effects. As mentioned above, the treatment increased motivation to change and use of protective behavioral strategies more than controls at 1 month, and the study also found that shifts in these variables predicted lower cannabis use at 6 months. Together, this suggests the intervention may work by activating these underlying mechanisms of change. Importantly, however, since the intervention and control had similar outcomes despite the intervention doing better on these potential mechanisms (e.g., readiness and protective behavioral strategies), there are likely many other important theoretical factors explaining how young adults modify their cannabis use over time.
Surprisingly, the text message-delivered intervention based on sound psychological and proven intervention principles did not outperform the waitlist control in directly reducing cannabis use over time. However, it did increase motivation to change and the use of protective behavioral strategies, 2 factors that were shown to predict reduced cannabis use at 6 months. That said, despite the treatment working as intended, the similar outcomes for intervention and control mean that there are many other theoretical factors explaining how young adults modify their cannabis use over time. Also of note, though peer influence is a well-established factor in substance use and recovery, and this intervention was designed to create positive shifts in peer networks, the intervention did not produce changes in peer network health, which may require more time or more intensive approaches to be impactful.
These findings are consistent with results from a prior pilot study by the same authors, which also tested the Peer Network Counseling text message-delivered intervention and found no direct effect on heavy cannabis use. Similarly, other digital interventions aimed at reducing cannabis use have failed to outperform controls that included education alone. One possible explanation is that the act of completing study assessments may have prompted self-directed behavior change – a phenomenon known as measurement reactivity, where the process of tracking behavior itself can lead to change. For example, social network improvements were similar between groups, suggesting the participants who did not receive the text message intervention also made changes that helped improve their cannabis use. This raises the question of whether the intervention offers added value beyond simple behavior tracking, especially when considering the additional cost and effort of delivering a structured program. However, text message-delivered and other digital interventions vary in their effectiveness. For example, a recent trial of a text message-delivered intervention in adults for reducing alcohol use showed significant improvements in drinking outcomes at 6 months, beyond what was achieved through drink tracking alone. Further research is needed to better understand why similar results have not been consistently observed for cannabis-focused digital interventions in young adults.
Regarding mechanisms of change, findings were mixed when compared to prior research. Earlier studies have supported 3 targeted mechanisms – positive shifts in one’s peer network, readiness to change, and protective behavioral strategies. This text message-delivered adaptation led to increases in motivation to change and use of protective behavioral strategies, but did not produce changes in peer network health. One important caveat is that the study was conducted during the COVID-19 pandemic, a period when limited social interaction may have reduced the influence of peers; though this would be expected to impact groups equally given the randomized design. Notably, the intervention increased readiness to change at 1 month compared to control, which was then associated with reduced cannabis use at 6 months. This finding is consistent with the motivational interviewing framework, which has strong empirical support for reducing substance use. Similarly, increased use of protective behavioral strategies was also linked to reduced cannabis use at 6 months. This aligns with prior research and may reflect a broader pattern among young adults who may be open to reducing cannabis-related harms without pursuing abstinence or in-person treatment. In this context, flexible and accessible digital intervention formats may be particularly well-suited to meet the needs of this population.
A brief, text message-delivered intervention did not reduce cannabis use more than a waitlist control, and was found to promote reductions indirectly by increasing motivation to change and encouraging the use of protective behavioral strategies. Given the widespread, daily use of smartphones among young adults, scalable and low-cost digital interventions may offer meaningful public health benefits, particularly for individuals who prefer to self-manage their cannabis use or are unwilling or unable to engage in traditional, in-person treatment. However, for young adults who are already motivated to change their cannabis use, simply tracking cannabis use over time may be just as effective as receiving a structured peer network counseling text message program. Future research is needed to explore how digital tools can be optimized or combined with other supports to enhance their effectiveness.
Mason, M. J., Coatsworth, J. D., Riggs, N. R., Russell, M., Mennis, J., Zaharakis, N., & Brown, A. (2025). Text message-delivered cannabis use disorder treatment with young adults: A large randomized clinical trial. Journal of Substance Use and Addiction Treatment, 170. doi: 10.1016/j.josat.2024.209611.
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