Mediational mechanisms involved in the relation between attachment insecurity and depression: A meta-analysis

Background: Several studies have investigated the intermediate variables or mediators through which attach-ment insecurity influence the development of depression. However, there has not been a systematic synthesis of this literature to date. The current meta-analytic review aimed at identifying such mediators and quantifying their effect size. Methods: We systematically searched Medline, Pubmed, Psycinfo, Embase, Proceedings Web of Science and ProQuest Dissertations & Theses Global up until May 2019. 108 studies met inclusion criteria (i.e., investigated intermediate variables that explain the effect of attachment insecurity [exposure] on depressive symptoms [outcome]). Standardized regression coefficients of the indirect and total paths of mediation models of 80 studies were pooled using the inverse of their variance as a weight. Studies were coded and ranked for quality. Results: Dysfunctional attitudes (beta = 0.10, 95% CI = 0.01 to 0.20), self-criticism (beta = 0.17, 95% CI = 0.04 to 0.28), low self-compassion (beta = 0.16, 95% CI = 0.02 to 0.29), and cognitive hyperactivating regulation strategies (beta = 0.13, 95% CI = 0.05 to 0.20), such as repetitive thinking (beta = 0.17, 95% CI = 0.07 to 0.28), and particularly, brooding rumination beta = 0.20, 95% CI = 0.07 to 0.32), mediated the association between insecure attachment and depressive symptoms. Indirect effects were only significant among adult populations. Limitations: The methodological quality of studies was mostly moderate to low and analyses revealed considerable heterogeneity. Conclusion: Our findings support the direct targeting of cognitive-emotional psychological mechanisms in prevention programs and treatment of depression. More longitudinal studies are needed to clarify the interplay of such mediators along with other interpersonal factors between insecure attachment and depression.