From 2018 to 2021, completion rates in US adolescents for CUD aged 12 to 17 years of age were similar and low. Specifically, the percentages for completion rates ranged from 36.9% in 2019 to 33.8% in 2021. The most common reasons for not completing treatment in all years were dropping out of treatment, transferring to another facility, and being terminated by the facility. These findings reflect well-documented challenges in adolescent substance use treatment [13] and are compatible with prior research indicating that traditional treatment approaches have not yielded satisfactory retention and abstinence rates. For instance, in a study evaluating adaptive treatment (AT) strategies for adolescents who struggled to achieve abstinence, only 37% of them completed the AT phase, and just 27% successfully achieved abstinence [14]. Both studies highlight the need for innovative, integrative approaches to enhance treatment efficacy. Incorporating wraparound services, addressing social determinants of health, and integrating family and community-based interventions may improve engagement and outcomes in this population.

In addition, the findings of the present study show that males were less likely to complete treatment than females. However, the narrowing gender gap in cannabis use as it becomes more socially accepted among females may complicate these trends [1,15]. Black and White adolescents also had lower completion rates. These patterns align with national data indicating higher cannabis use among males and Black adolescents but lower access to and completion of treatment [16,17]. Despite the overall increase in recreational cannabis use following legalization [18], Black and White adolescents may face unique barriers that limit their likelihood of success in treatment programs in conjunction with likely a wider acceptance of cannabis as a social drug. These disparities highlight the urgent need for tailored interventions that address the unique socioeconomic and cultural needs and beliefs and acceptability of cannabis in these racial/ethnic populations as perhaps a safe drug.

Furthermore, adolescents in dependent living arrangements had higher treatment completion rates, while those in independent or homeless situations showed significantly lower success rates. Youth experiencing homelessness face disproportionately high rates of mental health and substance use challenges, making treatment engagement and completion more difficult [13,19,20]. These findings further emphasize the need for tailored interventions that address both housing stability and early prevention strategies, particularly for vulnerable youth experiencing homelessness and comorbid mental health issues. Ensuring access to stable housing and providing early interventions could improve treatment engagement and outcomes for these at-risk populations [21].

Early cannabis use also emerged as a strong predictor of lower treatment completion. Adolescents who begin using cannabis at younger ages tend to develop more severe substance use disorders, which compounds the challenges in completing treatment. Research consistently links early cannabis initiation with worse cognitive, psychological, and social outcomes [4], which further complicates recovery efforts. These findings highlight the critical need for earlier intervention to prevent substance use initiation, particularly for cannabis. Evidence shows that a significant proportion of adults admitted to substance use treatment began using substances as early as age 11 or younger [22]. Adolescents who started using cannabis before age 15 had notably lower treatment completion rates, underscoring the importance of beginning prevention efforts in elementary or middle school.

Existing prevention programs that focus on “zero tolerance” have proven ineffective, highlighting the need for culturally relevant, evidence-based alternatives that are both inclusive and multifaceted [23,24]. Approaches that incorporate parent training and community involvement have shown promising results in early intervention efforts. Investing in research to develop and test such interventions is critical, especially for younger children, and should be sustained through middle and high school, when substance use typically accelerates [25]. Engaging parents, families, and communities in prevention initiatives, as well as communicating the importance of early intervention to policymakers and stakeholders, is key to expanding and improving these efforts. Comprehensive strategies addressing these needs could help reduce the number of adolescents who develop severe substance use disorders, improving treatment outcomes in later years.

Referral sources played a significant role in treatment outcomes in this study, with adolescents referred by schools, employers, or the legal system exhibiting higher completion rates compared to those who self-referred. This may reflect external pressures, such as compliance with school or court requirements, which can motivate adherence. However, such pressures do not necessarily foster intrinsic motivation or ensure long-term recovery. Leveraging these external support systems while simultaneously addressing internal motivators for sustained behavioral change is essential for improving outcomes. This underscores the critical importance of external support structures, particularly in environments such as schools, where adolescents can be monitored more closely. The findings highlight the value of strengthening collaborations between educational institutions and treatment providers, which could improve both treatment retention and overall success for adolescents with CUD. By funding school-based treatment programs and fostering partnerships between education and health care systems, these collaborations can ensure more effective referral processes and tailored interventions that better meet adolescents’ needs.

Furthermore, one of the key factors influencing treatment outcomes was the length of stay. In particular, stays ranging from 4 to 12 months were linked to a higher likelihood of completing CUD treatment. Similar findings have been observed in previous studies in non-adolescent populations [26] while others indicate that 90 days is the minimum recommended duration for treatment across substances [13]. As cannabis becomes more widely available, the demand for longer, more effective, and potentially more comprehensive treatments for CUD, especially for vulnerable populations such as adolescents, is likely to grow [26].

This study has some unique advantages. The data derive from a large, nationally representative sample of clients. This enhances the generalizability of our findings across diverse adolescent populations. However, several limitations must be noted. The reliance on self-reported data may introduce biases such as underreporting and social desirability bias. In addition, the data set only includes facilities receiving public funding, limiting the generalizability to private treatment centers or other settings. The data set focuses on discharge outcomes, lacking insight into long-term recovery and relapse rates, which are critical to fully understanding treatment success. The absence of detailed information on certain outcomes, such as the specific reasons (e.g., personal, systemic, or logistical barriers) for dropping out of treatment, restricts our ability to gain deeper insights into treatment completion. The data set also does not have details on therapeutic interventions and medications used, limiting the ability to evaluate treatment approaches, such as behavioral therapies or pharmacological treatments, relative to treatment completion. While cannabis use frequency at admission and discharge is captured, significant missing data, particularly in adolescents, prevented its inclusion in this analysis. Moreover, treatment completion is widely considered a critical milestone, as it is associated with better post-treatment outcomes in other substance use disorders. However, the lack of follow-up or longitudinal data on post-discharge relapse or functional outcomes limits the scope of conclusions we can draw. Finally, this study lacks data on key psychosocial vulnerabilities such as trauma history, adverse childhood experiences, family dynamics, peer influence, educational challenges, and access to social support systems, all of which are critical in shaping the trajectory of treatment outcomes in young people.

These limitations in the present study underscore the need for future research that includes longitudinal data to evaluate sustained recovery and relapse rates among adolescents, as well as more comprehensive data on treatment modalities and cannabis use patterns. In addition, it is important to gather detailed reliable data on cannabis use, including frequency, type of product, quantity, and methods of consumption. To better understand treatment engagement and outcomes, psychosocial data such as adverse childhood experiences, family support structures, and other social determinants of health should also be collected. These factors are often closely linked to substance use behaviors and treatment success. Investigating the impact of co-occurring mental health disorders, which significantly affect treatment outcomes, is also critical. Lastly, culturally tailored interventions should be prioritized to address treatment disparities and improve retention rates in this vulnerable population.