Living Alone May Push Young Adults Out of Addiction Treatment Early, Chilean Study Finds

Young adults in Chile who live alone are significantly more likely to abandon treatment for substance use disorders than their peers who live with family or with a partner and children, according to a sweeping new analysis of nearly 24,000 patients treated in the country’s public health system. The findings, drawn from a decade of national treatment records, add compelling weight to a growing body of evidence that the architecture of a person’s daily life, particularly who they come home to, can shape whether recovery takes hold or collapses. For a demographic already at high risk of falling through the cracks of addiction services, the study suggests that a household may be as clinically consequential as any medication or counseling protocol.

Substance use disorders represent one of the most formidable public health burdens in the Americas, where they stand as the leading cause of premature death and disability. The scale of the problem is stark: substance use is implicated in a substantial share of deaths among the world’s adult population, and effective treatment remains one of the most powerful tools available for reducing that toll. Yet treatment only works if people stay in it. Dropout is a persistent and corrosive weakness across virtually every model of addiction care, shortening exposure to interventions, undermining therapeutic momentum, and returning patients to the very environments that may have fueled their substance use in the first place. Understanding who drops out, and when, has therefore become a central question for researchers and clinicians alike.

The new research, published in Addiction Science & Clinical Practice, turned to an unusually rich source of evidence: Chile’s national registry of patients receiving publicly funded treatment for substance use disorders between 2010 and 2019. The investigators focused on emerging adults, those aged 18 to 29, a developmental window marked by instability, identity formation, and heightened vulnerability to both substance use and treatment disengagement. From the registry they assembled a retrospective cohort of 23,979 young adults and classified each person’s living arrangement at the moment they entered treatment into three categories: living alone, living with family of origin, or living with a partner and children. The question was deceptively simple. Did the shape of a patient’s household predict how long they stayed in treatment?

Answering it rigorously required sophisticated statistical machinery. People who live alone are not randomly different from those who live with family; they may differ in age, severity of addiction, employment, education, mental health, and a host of other characteristics that independently influence retention. To disentangle these threads, the researchers used inverse probability of treatment weighting, a technique built on multinomial logistic propensity scores that statistically balances the comparison groups on observed baseline differences. Survival analysis methods, including weighted Kaplan–Meier estimation, were then applied to track how the probability of remaining in treatment evolved over time. The team also computed the restricted mean survival time, a measure that captures the average duration of retention within a defined window and offers an intuitive summary of the survival curves that complements traditional hazard-based approaches.

Crucially, the analysis was stratified by treatment setting, separating outpatient programs from inpatient and residential care, because the two environments place very different demands on patients. The results painted a consistent picture. Young adults living with their family of origin or with a partner and children had a higher probability of remaining in treatment than those living alone, and the gap was widest in inpatient programs. At six months, the probability of still being in treatment was 0.54 for those living with family of origin and 0.57 for those living with a partner or children, compared with just 0.41 for those living alone. At twelve months, the pattern held: 0.43 and 0.44 for the cohabiting groups against 0.33 for those living solo. In other words, nearly six in ten socially connected patients were still engaged at the six-month mark in inpatient care, while fewer than half of those living alone remained.

The restricted mean survival time analysis reinforced the message. Among inpatient participants, the one-year RMST reached 0.60 for those living with family of origin and 0.62 for those living with a partner or children, but only 0.49 for those living alone, a retention gap that translates into weeks of additional engagement over the first year of care. Notably, the two cohabiting groups did not differ from each other in the inpatient setting; whether the anchor was parents, siblings, or one’s own partner and children, the protective effect of shared living appeared comparable. Outpatient programs told a subtler story. There, the differences between living arrangements were modest, and the most consistent contrast emerged between those living with family of origin and those living with a partner and children, suggesting that the protective architecture of the household may interact with the intensity and structure of the treatment modality itself.

Why would a shared household buffer against dropout? The authors point to the central role of social bonds. Family members and partners can provide practical scaffolding, transportation to appointments, reminders, financial support, a stable place to sleep, as well as emotional accountability, the diffuse but powerful sense that someone notices when you fail to show up. For emerging adults, whose ties to education, employment, and institutions are often still fragile, these bonds may carry particular weight. Residential and inpatient treatment, which requires a deliberate withdrawal from daily life, may be especially difficult to sustain without a household invested in one’s return and recovery. Conversely, young adults living alone may face treatment environments that inadvertently ask them to be their own support system, a demand that substance use disorders themselves make harder to meet.

The study’s implications reach well beyond Chile. Many national treatment systems, including those in high-income countries, collect detailed clinical data on substance use severity, psychiatric comorbidity, and treatment modality, yet rarely capture living arrangements as a structured variable at intake. This research suggests that a single intake question, who do you live with, could help identify patients at elevated risk of early disengagement and trigger targeted supports, from peer outreach and case management to deliberate family involvement in treatment planning. The findings also resonate with systems and family therapy traditions that view addiction not merely as an individual pathology but as a condition embedded in relational networks. Interventions that strengthen those networks, or that compensate for their absence, may hold untapped value for the youngest and most precarious patients.

Certain caveats deserve emphasis. As a retrospective cohort study, the analysis can establish association but not causation; unmeasured characteristics, such as motivation for recovery, quality of family relationships, or neighborhood context, could partly explain the observed differences. Living arrangements were assessed at treatment entry and may have changed during follow-up. The study also examined public-sector treatment in a single country, and Chile’s specific service configuration may shape how household context interacts with care. Nevertheless, the sheer size of the cohort, the decade-long observation window, and the rigor of the statistical design give the findings unusual credibility for observational research in this field, and Chile’s advanced monitoring infrastructure makes the dataset one of the strongest of its kind in Latin America.

The broader lesson is one that clinicians and policymakers are increasingly being asked to internalize: recovery is not enacted in a vacuum. For young adults, the developmental crucible in which identities, careers, and relationships are forged, the presence of a stable relational anchor may be the difference between a treatment episode that endures and one that dissolves within months. As the authors conclude, effective strategies for substance use disorders must take social support into account, recognizing the potential positive impact of familial and relational bonds during the critical phase of emerging adulthood. In a decade of data from nearly 24,000 patients, the signal is difficult to ignore: the people waiting at home may be among the most powerful, and least expensive, therapeutic assets a treatment system has.

Subject of Research: The association between living arrangements and time to dropout from substance use disorder treatment among emerging adults in Chile.

Article Title: Association between living arrangements and time to drop out in patients between 18 and 29 years of age, under treatment for substance abuse disorders in Chile, 2010–2019

Article References: Association between living arrangements and time to drop out in patients between 18 and 29 years of age, under treatment for substance abuse disorders in Chile, 2010–2019. (n.d.). https://doi.org/10.1186/s13722-026-00721-y

Image Credits: AI Generated

DOI: 10.1186/s13722-026-00721-y

Keywords: substance use disorders, treatment dropout, living arrangements, emerging adults, treatment retention, social support, inpatient treatment, outpatient treatment, Chile, survival analysis, family bonds, public health