Factors Associated With Treatment Non-Completion Among Adolescents and Young People With Substance Use Disorders in Low- and Middle-Income Countries: A Systematic Review

When a young person begins to struggle with drugs or alcohol, the path to recovery is rarely a straight line. It often involves entering a treatment program, only to leave before it is finished. This early departure, known in medical terms as treatment non-completion, is a significant hurdle. For adolescents and young adults, the stakes are particularly high because their brains are still developing, and their lives are deeply intertwined with school, family, and community. While doctors and researchers in wealthy nations have studied why young people drop out of these programs, much of the world remains a mystery. In low- and middle-income countries, where resources are scarcer and family structures can differ, the reasons a young person might stop treatment are less understood. Without this knowledge, it is difficult to build programs that actually keep them engaged long enough to heal.

A team of researchers set out to map this unknown territory. They conducted a systematic review, a rigorous method where scientists gather every available study on a specific topic to see the full picture. Their goal was to find out what factors are linked to young people leaving substance use treatment early in low- and middle-income countries. They focused specifically on individuals between the ages of ten and twenty-five, looking for patterns in why they might quit. The researchers searched through thousands of records from medical and psychological databases, including sources specific to Africa and the Americas, to find studies that reported on dropout rates or the reasons behind them. They were looking for any evidence, whether it came from a large hospital or a small community clinic, that could explain the difference between a young person who stays the course and one who walks away.

The search yielded a surprisingly small number of studies that met their strict criteria. Out of the hundreds of records they reviewed, only five studies from three countries—Brazil, Mexico, and Türkiye—contained data specifically about young people in these regions. Together, these studies covered 430 participants. The findings revealed a stark reality: leaving treatment early is common. In one study of adolescents in Brazil, nearly two-thirds of the participants dropped out. In a Turkish study of young people in an inpatient hospital setting, the number was even higher, with more than three-quarters not completing their treatment. In another Brazilian study focusing on young women, only a tiny fraction remained in care after two years. The researchers noted that these numbers varied wildly because the studies looked at different types of treatment, from psychiatric hospitals to community programs, making it hard to compare them directly.

Despite the small number of studies, clear patterns began to emerge regarding what helps a young person stay in treatment. One of the most consistent factors was school. In the studies that looked at it, young people who were still attending school or had not been expelled were more likely to finish their treatment. Conversely, those who had been suspended or were no longer in the classroom were at a much higher risk of dropping out. This suggests that staying connected to education might provide a structure or a sense of purpose that supports recovery. Family involvement also appeared to be a key piece of the puzzle. Studies described how having supportive parents or a family that was actively involved in the process helped young people remain engaged. In one qualitative study, participants spoke about how the relationship with staff and the relevance of the program to their lives mattered, but the broader data pointed to the family unit as a critical support system.

The type of substance being used also seemed to play a role, though the picture was not entirely clear. In two Brazilian studies, the use of cocaine or crack was linked to a higher likelihood of dropping out. However, the researchers found that other factors were harder to pin down. For instance, one study in Turkey found that young people using heroin were actually more likely to complete their treatment, but the authors cautioned that this might be due to the specific, highly structured nature of that hospital program rather than the drug itself. Similarly, while some studies looked at whether having other mental health issues like depression or attention problems affected retention, the evidence was too mixed to draw a firm conclusion. The researchers emphasized that these are associations, not proven causes; they show what tends to happen together, but they do not prove that one thing directly causes the other.

Perhaps the most significant finding was not what the studies said, but what they did not say. The review highlighted a massive gap in knowledge. There were no eligible studies from Sub-Saharan Africa or South Asia, two regions with huge populations of young people. This does not mean the research does not exist, but rather that it is either not being published in the databases the researchers searched, or it is not being reported in a way that allows it to be found. Furthermore, almost all the studies focused on formal, specialist medical services. The review found no evidence regarding informal, community-based, or faith-led treatment programs, which are often the primary source of care for young people in many low- and middle-income countries. This leaves a blind spot in our understanding of how young people in these regions actually access and stay in care.

The researchers concluded that while we have some clues, the evidence base is too small and too varied to make definitive rules. We know that keeping a young person in school and involving their family looks promising, but we cannot say for certain that these actions will guarantee success. The studies were mostly observational, meaning they watched what happened rather than testing specific solutions. To move forward, the authors argue that future research needs to be more precise. They call for studies that report age groups separately, use consistent definitions for what counts as "dropping out," and look at the many ways young people seek help outside of hospitals. Until these gaps are filled, health systems in low- and middle-income countries will be trying to build effective treatment programs without a complete map of the terrain. The path to keeping young people in recovery is there, but we need more light to see it clearly.