Distorted thoughts as a mediator of depressive symptoms in patients with major depressive disorder: a longitudinal study

BACKGROUND: Distorted thoughts are common in Major Depressive Disorder (MDD), and can impact patients’ perceptions of depression severity, and predict chronicity and treatment response. This study aimed to investigate whether distorted thoughts mediate depressive symptoms in MDD over a 6-month period. METHOD: These are secondary results from a study that followed 119 patients diagnosed with moderate to severe MDD for 6 months. Diagnoses were confirmed by the Structured Interview for DSM-IV (SCID-CV). The analysis was composed of results from the Hamilton Depression Rating Scale (HAMD-17), the Montgomery-Asberg Depression Rating Scale (MADRS), the second edition of the Beck Depression Inventory (BDI-II), and the Depression Thoughts Scale (DTS) collected at weeks 1, 8, 12 and 24. RESULTS: Results showed that the DTS mediated the relationship between depressive symptoms experienced approximately 3 months after starting antidepressant treatment. CONCLUSION: Cognitive distortions were linked as a mediator to depressive symptoms, highlighting the importance of early psychological interventions in patients with MDD who exhibit these distortions. TRIAL REGISTRATION: NCT02268487. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12955-023-02178-y.