Emotional and social loneliness in the longitudinal association between alexithymia and depressive symptoms

Background Alexithymia has been linked to depressive symptoms, yet the mechanisms underlying this association remain unclear. We examined whether emotional loneliness (perceived lack of close, intimate bonds) and social loneliness (perceived deficits in broader social integration) represent distinct pathways linking alexithymia to depressive symptoms. Methods In a longitudinal study of 2628 adults aged 18–40 years, we examined whether emotional and social loneliness mediate the association between alexithymia and depressive symptoms. Participants were assessed over 10 months (T0–T2). A parallel mediation model controlling for baseline loneliness and depressive symptoms was followed by a covariate-adjusted model additionally accounting for age, gender, education, place of residence, income, and anxiety. Results In the model without additional covariate adjustment, baseline alexithymia was associated with emotional (β = 0.110, p < 0.001) and social loneliness (β = 0.096, p < 0.001) at T1. Emotional loneliness at T1 was associated with higher depressive symptoms at T2 (β = 0.157, p < 0.001), whereas social loneliness was not (β = 0.015, p = 0.701). The indirect effect through emotional loneliness was significant (β = 0.017, p = 0.003), whereas that through social loneliness was not (β = 0.001, p = 0.709). The indirect effect through emotional loneliness was significantly stronger (difference: β = 0.016, p = 0.045). Findings remained robust after covariate adjustment. Conclusions The indirect prospective association between alexithymia and depressive symptoms was small but stronger through emotional than social loneliness. These findings highlight the potential relevance of qualitative aspects of loneliness to depressive symptoms.