| Abstract: |
This chapter coalesces broad, sweeping epidemiological data with the potential underlying biological constructs of depression as a systemic disease in the context of cancer. It attempts to look at depression from this broader view, informing how depression as a systemic disease may impact and interact with cancer. It is clear, in the converse, that having cancer leads to sadness, depressed mood, and existential concerns about life, and if depression worsens, then the physical symptoms of fatigue, asthenia, slow cognition, and apathy develop, which constitute a major depressive episode. It is this more severe form of depression, composed of both mental and physical symptoms, that is the focus of this chapter. The less severe forms of adjustment disorders and sub-syndromal depression are responses to illness and are common experiences for patients who are adapting to the cancer diagnosis and its treatments. At present, data do not support a malignant transformation potential resulting from depression or other emotional states, including grief. However, current research suggests that depression, dong with many other factors, may play a role in the metastatic progression of cancer mediated by the nervous system and the cancer environment (Le., tumor stroma). At an epidemiological level there are tantalizing data to suggest that the manifestations of depression such as social isolation and poor social support are associated with worse survival in the cancer setting. Specifically, the chapter reviews several putative mechanisms of biologically based depression in the cancer setting: (1) the cytokine hypothesis, (2) hypothalamicpituitary-adrenal (HPA) dysregulation, (3) abnormal diurnal cortisol rhythms, (4) glucocorticoid dysregulation, (5) enhanced sympathetic nervous system adrenergic activity, and (6) alterations in DNA protein products through transcription/epigenetics. Depression in the cancer setting has provided substantial insights into the biological basis of cancer through the small but growing field of psychoneuroimmunology. Technological advances in cancer (e.g., those that harness the immune system) and continued work in discovering the epigenetic imprint of social factors associated with depression promise to further elucidate this overlapping relationship. (PsycINFO Database Record (c) 2018 APA, all rights reserved) |
