Depression, Inflammation, and Cancer
Depression in cancer is common, often unrecognized and untreated, and has a significant impact on quality of life and morbidity and mortality. Increasing understanding of the impact of the immune system and inflammation on the brain has revealed that cancer patients are at an especially increased risk for inflammation-induced depression by virtue of the many sources of inflammation to which they are exposed. Treatments including surgery, radiation, chemotherapy, and immunotherapy as well as cancer itself are associated with increased inflammation that can drive brain changes and depression. This chapter will review the relationship between depression and inflammation in cancer patients with special attention paid to the data that support increased inflammatory markers in cancer patients with depression, the neurobiological mechanisms by which inflammation can impact neurotransmitters and neurocircuits in the brain, and the data addressing interventions that reduce inflammation and depression in cancer patients. Finally, the chapter addresses future directions regarding the translational implications of this work.