<p>Diabetes mellitus has emerged as a critical public health concern, not only due to its well-documented metabolic consequences but also because of its significant association with mental health disorders, particularly depression. This review aims to elucidate the intricate molecular mechanisms by which diabetes contributes to the development of depressive symptoms. We explore the growing body of evidence linking metabolic dysfunction with mood disorders, drawing insights from both animal models and clinical studies. Key molecular pathways are examined, including the enhancement of oxidative stress, the role of neuroinflammation, alterations in neurotrophic factors, and the induction of apoptosis. We also investigate how imbalances in neurotransmitters and insulin resistance serve as crucial links between diabetes and depression, alongside the implications of altered synaptic plasticity. By synthesizing these findings, we highlight the multifaceted relationship between diabetes and depression, ultimately advocating for integrated therapeutic approaches that address both conditions in order to improve patient outcomes and enhance overall well-being.</p> Graphical Abstract <p></p>