
In the 1950s and 1960s, researchers found that mice and rats subjected to stressful stimuli were more likely to develop viral infections and tumors than nonstressed animals (Miller, 1998). Today, that once-pioneering research in psychoneuroimmunology (PNI) has burgeoned into sophisticated clinical studies that look at, for example, how caregiving can affect the immune system, how stress may delay wound healing and how pretreatment with an antidepressant prevents cytokine-induced depression in therapy for cancer.