Living Alone Increases Suicide Risk in Depression and Anxiety

In a national cohort of 3.76 million adults in South Korea, living alone was associated with an increased risk of suicide. But when depression and/or anxiety were added to the mix, the risk increased exponentially. The most vulnerable group were men and middle-aged adults (40–64 years) living alone and with depression or anxiety. The study is published in JAMA Network Open.

Background

Suicide remains a leading cause of premature death worldwide, with South Korea having the highest rates among OECD countries for many years. At the same time, the structure of living arrangements is rapidly changing: the proportion of single-person households in Korea has reached a third of the population, increasing interest in the impact of living alone on health. It is important to distinguish between three related but not identical phenomena: living alone (the actual way of life), social isolation (the paucity of connections and contacts), and experienced loneliness (a subjective feeling). Living alone does not in itself equal isolation, but it often leads to it and is associated with worse physical and mental health outcomes.

Depression and anxiety disorders are well-documented risk factors for suicidal behavior. There is also evidence that living alone increases the risk of suicide and overall mortality. However, these two risk layers have typically been studied separately: studies on “living alone” often do not take into account active mental disorders, and studies on depression/anxiety rarely include the housing context. As a result, their combined contribution and possible synergy have remained unclear: does living alone increase the risk of suicide in people with depression/anxiety beyond the combined effect of each factor?

Additional reasons for focusing on Korea are socio-cultural conditions (stigma of mental disorders, high academic and work loads, fragility of family support in urban areas) that may reduce help-seeking and increase the vulnerability of people living alone with symptoms. Vulnerable groups are also heterogeneous: according to data from different countries, men and middle-aged people are more often in the high-risk zone, which requires verification on large representative arrays.

Thus, there is a need for a large population-based study with long-term follow-up, clear definition of “living alone” status (stable, not temporary), registration of depression/anxiety, and tracking of the outcome “death by suicide.” This allows (1) to quantify the individual and joint effects of living alone and mental disorders, (2) to test the robustness of the results after accounting for demographics, behavior, and somatic diseases, and (3) to identify groups at greatest risk for targeted prevention.

Why was this studied?

Living alone is not the same as isolation or loneliness, but it often leads to them. And living alone is becoming more common: in South Korea, the share of single-person households has reached 34.5%. At the same time, depression and anxiety are leading factors in suicide risk. Until now, it has rarely been looked at how these two layers of risk combine: everyday (how we live) and clinical (what about our mental health).

Who and how was studied

• Design: National cohort from the National Health Insurance Service of Korea.
• Start: people ≥20 years old who passed the mandatory check-up in 2009.
• Follow-up: until 2021 (average ~11 years).
• Result: death by suicide (according to the national registry of causes of death).
• Expositions:
  • Living alone (registered alone, stable for ≥5 years).
  • Depression and anxiety (based on medical codes for the previous year).
• Sample size: 3,764,279 individuals (mean age 47.2 years; 55.8% male).
  • Depression - 3.0%; anxiety - 6.2%; living alone - 8.5%.

Cox models successively adjusted for gender and age, income and habits, medical conditions, and comorbid mental disorders to separate the “signal” from the “noise.”

Key figures

Compared to people who did not live alone and did not have depression/anxiety:

• Living alone + depression and anxiety at the same time:
  AHR 6.58 (95% CI 4.86–8.92) – this is approximately +558% of the risk.
• Living alone + depression (without anxiety):
  AHR 3.91 (2.96–5.16) — about +290%.
• Living alone + anxiety (without depression):
  AHR 1.90 (1.48–2.43) — about +90%.
• Living alone, but without depression and anxiety:
  AHR 1.44 (1.35–1.54) — +44%.

Even among those who did not live alone, the presence of disorders was dangerous:
Depression - AHR 2.98, anxiety - AHR 1.64; and a combination of depression and anxiety - AHR 3.83.

Who is especially at risk?

In the subgroups the picture became more pronounced:

• Men living alone with depression: AHR 4.32.
• 40–64 years old, living alone with depression: AHR 6.02.
• With anxiety, there is the same trend: higher in men and in 40–64 year olds.

This is consistent with men being more likely to use more lethal methods and being less likely to seek help, and with loneliness in midlife being more often associated with relationship breakdown, loss, and career stress.

Why does this happen (probable mechanisms)

• Socially: Less “safety net” in the form of daily support, more chances that a crisis will go unnoticed. The stigma around mental health in Korea further inhibits seeking help.
• Psychologically, living alone increases isolation and feelings of hopelessness—key predictors of suicidal behavior.
• Biologically, chronic stress and isolation are associated with hypothalamic-pituitary-adrenal axis dysregulation and inflammation, which are associated with depression, anxiety, and suicide risk.

What does this mean for practice and policy?

• Screening should be “double-barreled.” For patients with depression/anxiety, asking about living alone and level of social support is as important as asking about symptoms.
• A marker that is visible. Unlike subjective loneliness, the fact of living alone is an easily noticeable characteristic for doctors, employers, and social services.
• Point measures:
  • proactive contacts (frequent check-ins) with those who live alone and have a diagnosis;
  • quick routes to help (crisis lines, mobile teams, telepsychiatry);
  • “social prescription” programs: interest clubs, volunteering, group trainings, where vulnerable people are helped to build a support network;
  • in companies - training managers to recognize red flags and developed ways to get help;
  • at the city level - community centers “within walking distance”, where you don’t have to “make an appointment with a doctor” to get into a warm social space.

Important Disclaimers

• The study is observational—it shows associations, not hard causation.
• Living alone was determined by registers; the dynamics of status over the years cannot be fully tracked.
• Depression and anxiety diagnoses by medical codes: stigma may underestimate actual prevalence.
• The results were obtained in the Korean context (culture, healthcare system) - transferability to other countries requires verification.

Conclusion

Living alone is an independent and easily identifiable “amplifier” of suicide risk in people with depression and anxiety. Men and middle-aged people are most vulnerable. This is not about “lifestyle is to blame”, but about the fact that clinical risk is supplemented by social risk – and it is this that can be specifically extinguished: early detection, close support and the creation of “social safety cushions”.