Loneliness is linked to psychological pain in both euthymic patients and healthy controls: a cross-sectional study

Psychological pain is a subjective distressing emotional experience associated with suicidal vulnerability independently of depressive symptom severity. Although it has been described in both clinical and non-clinical populations, little is known about psychosocial factors associated with psychological pain in euthymic patients with mood disorders and in non-clinical individuals. To investigate clinical and psychosocial factors associated with psychological pain in euthymic and non-clinical samples, with a particular focus on loneliness and childhood trauma. We included 133 euthymic patients (Inventory of Depressive Symptomatology (IDS-C 30) < 11 and Young Mania Rating Scale (YMRS) < 7) and 84 non-clinical participants. Psychological pain was defined using the Physical and Psychological Pain Visual Analog Scale (PPP-VAS) and suicidal ideation with the Columbia Suicide Severity Rating Scale (C-SSRS). Loneliness and anxiety were measured respectively by the University of California Los Angeles Loneliness Scale (UCLA) and the State-Trait Anxiety Inventory (STAI-T). Childhood trauma was evaluated using the Childhood Trauma Questionnaire (CTQ). Analyses were conducted separately in each group. Both samples were predominantly female (76% in euthymic participants and 69% in non-clinical sample) with a mean age of 40 ± 14 and 37 ± 12 years respectively. Only loneliness was associated with psychological pain in both euthymic (β = 0.058, p-value = 0.030) and non-clinical samples (β = 0.063, p-value = 0.053). Childhood trauma moderated this association in non-clinical participants (β = -0.007, p-value = 0.029, adjusted effect size R² = 0.09). Loneliness appears to be a key psychosocial correlate of psychological pain in both euthymic and non-clinical populations. These findings support the importance of considering interpersonal factors in the assessment of psychological pain beyond acute mood episodes and to develop interventions targeting loneliness to reduce psychological pain and related negative consequences. This study was conducted in accordance with the French Reference Methodology MR-004 (CNIL) for research using health data that does not involve human participants. According to this framework, registration in a clinical trial registry is not required. The study was registered in the public directory of the Health Data Hub, as required for MR-004 studies, on the 26-03-2025.