The association of material deprivation with major depressive disorder and the role of loneliness and social support: A cross-sectional study

Background: Existing research has highlighted the positive association of material deprivation, loneliness, and poor social support with major depressive disorder (MDD). However, there is limited information on the complex interplay between these risk factors. In this study, we investigated (1) whether loneliness and social support moderate the relationship between material deprivation and MDD and (2) whether social support moderates the association between material deprivation and loneliness. Methods: We conducted a cross-sectional study analyzing responses from a representative sample of the Spanish adult population, comprising 2790 individuals who were interviewed between 2019 and 2021. The 12-month prevalence of MDD was assessed using the Composite International Diagnostic Interview (CIDI). Loneliness was measured using the three-item UCLA Loneliness Scale, and social support was evaluated with the Oslo social support scale. Material deprivation was measured using an instrument developed by the Spanish National Institute of Statistics (INE). Regression models were constructed to investigate moderating effects. Results: About 25 % of participants experienced material deprivation and 2.8 % had MDD. Among those with lower levels of loneliness, the probability of MDD was almost 0.10 and no significant differences were found in relation to material deprivation. Conversely, differences depending on material deprivation ranged from 0.10 (95 % CI 0.03, 0.18) to 0.44 (95 % CI 0.24, 0.65) among those with higher levels of loneliness. Social support effectively moderated the association between material deprivation and loneliness. Limitation: The cross-sectional nature limits causal inferences. Conclusion: Social support has the potential to improve loneliness and mental health in individuals with economic difficulties.