Depression and breast cancer: research progress and prospects from an interdisciplinary perspective.

Depression and breast cancer are two major health concerns in the medical field today. Not only do they mutually influence the risk of onset and disease progression, but they also collectively lead to poorer clinical outcomes and reduced quality of life. This review elaborates on how depression, through the overactivation of the hypothalamic-pituitary-adrenal (HPA) axis, may be associated with persistently elevated levels of glucocorticoids (GCs). This, in turn, causes dysregulation of the sex hormone axis, prolactin imbalance, and insulin resistance, collectively promoting the initiation and progression of breast cancer. Meanwhile, the depressive state may suppresses the function of immune cells such as T cells and natural killer (NK) cells, and promotes the release of pro-inflammatory cytokines, thereby impairing immune surveillance and creating a favorable environment for tumor growth. Furthermore, imbalances in tryptophan metabolism and gut microbiota dysbiosis exacerbate neuroimmune dysregulation, forming a vicious cycle. In terms of treatment, standalone biomedical or psychological interventions have limited efficacy, necessitating an interdisciplinary and integrated approach. Pharmacological treatment requires attention to drug interactions between antidepressants and breast cancer medications such as tamoxifen. Psychological interventions, including cognitive-behavioral therapy, mindfulness-based yoga, and virtual reality technology, can effectively alleviate depressive symptoms and improve treatment adherence. Additionally, emerging approaches such as traditional Chinese medicine, neuromodulation techniques, and gut microbiota regulation show considerable potential for intervention. These findings provide new insights for understanding and clinically managing the comorbidity of depression and breast cancer.