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

The scale of the analysis is notable. The cohort consisted of patients recruited from addiction treatment centers across Quebec in 2012 and 2013 who received a diagnosis of gambling disorder at any point between 2009 and 2022. The investigators linked these clinical records with provincial health administrative databases, allowing them to track diagnoses, service use, and hospitalizations over more than a decade. Using the discharge date from each patient’s last hospitalization carrying a gambling disorder diagnosis as the index date, they identified 470 hospitalized patients and matched them by age and sex to 1,606 patients with gambling disorder who had never been hospitalized. Controls qualified only if they had received their gambling disorder diagnosis within the three years preceding the index date, a constraint designed to ensure that the two groups were genuinely comparable in the recency of their diagnosis.

Methodologically, the study relied on conditional logistic regression stratified by age and sex, a technique appropriate for matched case-control designs because it compares each case with its matched controls while automatically accounting for the matching variables. The models produced adjusted odds ratios, a statistical measure expressing how much each factor changes the odds of hospitalization after controlling for everything else in the model. This approach matters because hospitalization in psychiatric populations is rarely the product of a single cause; it emerges from an interplay of illness severity, treatment history, social circumstances, and the way health systems respond to crises. By separating these strands statistically, the researchers could ask which factors carry independent weight.

The answer, in descending order of magnitude, was striking. Patients with comorbid mental disorders in the three years before the index date had nearly ten times the odds of hospitalization compared with those without such comorbidity, an adjusted odds ratio of 9.81. Suicidal behaviors more than doubled the odds, at 2.88, and comorbid substance-related disorders raised them by more than half, at 1.58. These figures align with a growing international literature. A Finnish nationwide register study published in Addiction in 2024 documented elevated somatic and psychiatric comorbidity among people with diagnosed gambling disorder, and a systematic review and meta-analysis in the Australian and New Zealand Journal of Psychiatry found psychiatric comorbidity to be the rule rather than the exception among treatment-seeking problem gamblers. Research from Denmark has similarly linked gambling disorder treatment with heightened comorbidity, criminality, and healthcare costs.

The suicide signal deserves particular emphasis. Gambling disorder carries one of the highest suicide rates of any addiction, and studies of treatment samples in Austria and national inpatient data in the United States have repeatedly documented elevated rates of suicidal ideation and attempts among people with gambling problems, especially when depression is present. The Quebec findings quantify this danger in service terms: a history of suicidal behavior in the preceding three years nearly triples the odds that a patient with gambling disorder will require hospitalization. For clinicians, this suggests that suicide risk assessment should be a routine, systematic component of every encounter with a patient receiving treatment for gambling disorder, not an occasional add-on reserved for obvious crises.

Service use patterns in the year before the index date also proved predictive. High emergency department use carried an adjusted odds ratio of 2.45, and any hospitalization in the prior year raised the odds by 79 percent. These findings echo a broader pattern documented in patients with substance-related disorders, where frequent emergency department visits and prior hospitalizations reliably flag patients at risk of subsequent acute care. Emergency departments, in this sense, function as early warning systems, but also as symptoms of a system under strain. Studies of frequent emergency department visitors have shown that these patients often report unmet primary care needs, suggesting that heavy emergency use reflects gaps in community-based care rather than simply greater illness. The Quebec data now extend that insight to the gambling disorder population.

Perhaps the most actionable findings concern what protects patients. High-intensity outpatient care in the year before the index date halved the odds of hospitalization, with an adjusted odds ratio of 0.50, and high continuity of care reduced the odds by 26 percent, at 0.74. Continuity of care, a concept with a long history in health services research dating back to work on primary care in the 1970s, refers to the extent to which a patient sees the same providers or a coherent team over time rather than a rotating cast of strangers. Research on patients with serious mental illness has shown that family practice continuity reduces unplanned hospital use, and studies of general practitioner regularity have linked it to lower rates of high-use hospitalization. The Quebec study demonstrates that the same principle applies to behavioral addiction: patients whose outpatient care is intensive and consistent are markedly less likely to crash into the acute care system.

Sociodemographic factors added their own texture. Unemployment raised the odds of hospitalization by 45 percent, and living in semi-urban or rural areas increased them by 51 percent, a pattern that likely reflects both the socioeconomic stress associated with joblessness and the thinner supply of specialized addiction services outside major urban centers. Intriguingly, living alone was associated with lower odds of hospitalization, at 0.61, a counterintuitive result the authors note as significant. One possible interpretation is that patients living alone who reach treatment may differ systematically from those with co-residing partners or family, or that cohabiting patients are more often pushed into care by distressed relatives at moments of crisis that otherwise might have escalated to hospitalization. The authors frame the overall picture through the lens of vulnerability: unemployment, rural residence, and social isolation mark patients whose clinical needs intersect with limited community support.

The study’s framework draws on Andersen’s behavioral model of health services use, a foundational framework in health services research that organizes predictors into predisposing, enabling, and need characteristics. This theoretical scaffolding helps explain why both clinical severity and service system factors appear side by side in the results. Gambling disorder, classified as a behavioral addiction in both the DSM-5 and the ICD-11, remains frequently underdiagnosed and undertreated, partly because of stigma. Research on perceived social stigmatization of gambling disorders shows that stigma deters help-seeking and shapes how patients and professionals view treatment, while systematic reviews of general practitioners’ management of gambling disorder reveal persistent gaps in knowledge and screening. Patients may therefore cycle through primary care and emergency departments with depression, anxiety, or substance problems while the underlying gambling disorder goes unrecognized.

The Lancet Public Health Commission on gambling, published in 2024, framed gambling as a significant and growing public health concern, and the Quebec study adds a concrete service-delivery dimension to that call. The authors’ conclusion is direct: the key clinical needs and vulnerabilities among patients with gambling disorder should be addressed through outpatient interventions that prioritize high continuity and intensity of care. In practical terms, that means building treatment pathways in which a patient with gambling disorder sees a stable, coordinated team that can manage comorbid depression, screen for suicide risk, treat concurrent substance use, and maintain contact over time, rather than relying on episodic crisis-driven care. The chronic disease management model long advocated for addiction, which treats addiction as a relapsing condition requiring sustained monitoring rather than a discrete episode to be cured, fits these findings closely. As jurisdictions worldwide expand legalized gambling and online platforms multiply access, the population of diagnosed patients will likely grow, and the Quebec data offer a template for identifying, early and precisely, those most at risk of hospitalization, and for designing the outpatient systems that could keep them out of hospital beds altogether.

Subject of Research: Clinical, service use, and sociodemographic predictors of hospitalization among patients diagnosed with gambling disorder in Quebec, Canada.

Article Title: Predictors of Hospitalization Among Patients with Gambling Disorder: a Retrospective Matched Case–Control Study

Article References: Predictors of Hospitalization Among Patients with Gambling Disorder: a Retrospective Matched Case–Control Study. (n.d.). https://doi.org/10.1007/s11469-026-01729-w

Image Credits: AI Generated

DOI: 10.1007/s11469-026-01729-w

Keywords: gambling disorder, hospitalization, comorbid mental disorders, suicidal behavior, substance-related disorders, emergency department use, continuity of care, outpatient treatment, case-control study, Quebec, behavioral addiction, health services research