Longitudinal associations between loneliness and outcomes of Common Mental Disorders (CMDs): A systematic review and meta-analysis.
7 affiliations
- 1Division of Psychiatry, University College London (UCL), London, UK. [email protected].
- 2Centre for Outcomes Research and Effectiveness (CORE), Research Department of Clinical, Educational & Health Psychology, University College London (UCL), London, UK.
- 3Division of Psychiatry, University College London (UCL), London, UK.
- 4North London NHS Foundation Trust, London, UK.
- 5Institute of Psychiatry, Psychology & Neuroscience, King's College London, London, UK.
- 6Department of Psychology, Kingston University, London, UK.
- 7Camden & Islington NHS Talking Therapies for anxiety and depression services, North London NHS Foundation Trust, London, UK.
Abstract
Background
Loneliness has been increasingly associated with poor mental health outcomes, yet its prognostic role in people with Common Mental Disorders (CMDs) remains unclear. This systematic review aimed to examine whether loneliness is longitudinally associated with mental health outcomes in individuals with CMDs, regardless of treatment status.Methods
We searched PsycINFO, MEDLINE, Embase and CINAHL from inception to October 2025 for longitudinal studies examining associations between baseline loneliness and CMD outcomes at follow-up. Eligible studies included adults aged 16+ with CMDs. We conducted a narrative synthesis and where appropriate, random-effects meta-analyses for binary depression outcomes reflecting unfavourable course (recurrence, persistence, or non-remission). Study quality was assessed using the Newcastle-Ottawa Scale, and certainty of evidence was evaluated using GRADE. The protocol was registered with PROSPERO (registration number: CRD42023410401).Results
We included 22 studies, of which the majority focused on depression-related outcomes (operationalised as symptom severity, recurrence, persistence, remission, and service utilisation). Our narrative synthesis showed consistent associations between higher baseline loneliness and poorer depression-related outcomes at follow-up in people with CMDs across clinical, community, and treatment settings. Meta-analysis of four studies (all in older adults with depression) showed that individuals reporting loneliness at baseline had over three times the odds of poor depression outcomes at follow-up compared with those not lonely (pooled adjusted OR 3.26, 95% CI [2.26-4.70], p < 0.001). This finding should be interpreted with caution, as only one of the four studies adjusted for baseline depressive symptom severity. The few studies capturing suicidal ideation, anxiety, and mixed CMD outcomes found limited and inconsistent evidence. The GRADE certainty of evidence was high for depression outcomes, low for suicidal ideation and anxiety outcomes, and very low for mixed CMD outcomes.Conclusions
Loneliness is consistently associated with poorer subsequent depression outcomes in people with CMDs, particularly depressive disorders. These findings suggest loneliness may represent an important prognostic factor in depression and warrant further evaluation in intervention studies. Further high-quality longitudinal research is needed to clarify whether-and under what conditions-loneliness affects outcomes for other CMDs and treatment effectiveness.
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BibTeX
@article{stefanidou2026longitudinal,
title = {{Longitudinal associations between loneliness and outcomes of Common Mental Disorders (CMDs): A systematic review and meta-analysis.}},
author = {Theodora Stefanidou and Siying Li and Kinga Lagan and Gamze Evlat and Hannah Gray and Jasmine Harju-Seppänen and Amber Jarvis and Millie O'Sullivan and Shivangi Talwar and Gemma Lewis and Joshua E J Buckman and Alexandra Pitman and Sonia Johnson and Brynmor Lloyd-Evans},
journal = {BMC medicine},
year = {2026},
month = oct,
doi = {10.1186/s12916-026-05252-6},
url = {https://europepmc.org/article/MED/42875771},
note = {CC BY},
}
RIS
TY - JOUR
TI - Longitudinal associations between loneliness and outcomes of Common Mental Disorders (CMDs): A systematic review and meta-analysis.
AU - Theodora Stefanidou
AU - Siying Li
AU - Kinga Lagan
AU - Gamze Evlat
AU - Hannah Gray
AU - Jasmine Harju-Seppänen
AU - Amber Jarvis
AU - Millie O'Sullivan
AU - Shivangi Talwar
AU - Gemma Lewis
AU - Joshua E J Buckman
AU - Alexandra Pitman
AU - Sonia Johnson
AU - Brynmor Lloyd-Evans
PY - 2026
DA - 2026/10/03
JO - BMC medicine
DO - 10.1186/s12916-026-05252-6
UR - https://europepmc.org/article/MED/42875771
AB - Background Loneliness has been increasingly associated with poor mental health outcomes, yet its prognostic role in people with Common Mental Disorders (CMDs) remains unclear. This systematic review aimed to examine whether loneliness is longitudinally associated with mental health outcomes in individuals with CMDs, regardless of treatment status.Methods We searched PsycINFO, MEDLINE, Embase and CINAHL from inception to October 2025 for longitudinal studies examining associations between baseline loneliness and CMD outcomes at follow-up. Eligible studies included adults aged 16+ with CMDs. We conducted a narrative synthesis and where appropriate, random-effects meta-analyses for binary depression outcomes reflecting unfavourable course (recurrence, persistence, or non-remission). Study quality was assessed using the Newcastle-Ottawa Scale, and certainty of evidence was evaluated using GRADE. The protocol was registered with PROSPERO (registration number: CRD42023410401).Results We included 22 studies, of which the majority focused on depression-related outcomes (operationalised as symptom severity, recurrence, persistence, remission, and service utilisation). Our narrative synthesis showed consistent associations between higher baseline loneliness and poorer depression-related outcomes at follow-up in people with CMDs across clinical, community, and treatment settings. Meta-analysis of four studies (all in older adults with depression) showed that individuals reporting loneliness at baseline had over three times the odds of poor depression outcomes at follow-up compared with those not lonely (pooled adjusted OR 3.26, 95% CI [2.26-4.70], p < 0.001). This finding should be interpreted with caution, as only one of the four studies adjusted for baseline depressive symptom severity. The few studies capturing suicidal ideation, anxiety, and mixed CMD outcomes found limited and inconsistent evidence. The GRADE certainty of evidence was high for depression outcomes, low for suicidal ideation and anxiety outcomes, and very low for mixed CMD outcomes.Conclusions Loneliness is consistently associated with poorer subsequent depression outcomes in people with CMDs, particularly depressive disorders. These findings suggest loneliness may represent an important prognostic factor in depression and warrant further evaluation in intervention studies. Further high-quality longitudinal research is needed to clarify whether-and under what conditions-loneliness affects outcomes for other CMDs and treatment effectiveness.
SN - 1741-7015
ER -