Page 147 - Encyclopedia of Nursing Research

114 n DEPRESSion AnD CARDioVASCULAR DiSEASES

is evidence to indicate that depression may investigate the relationship between inflam-
contribute to increased incidence of cardio- mation, depression, and cardiovascular dis-
D vascular events. This effect may be mediated ease are justified. Large, randomized clinical
by other behavioral and biological factors trials are needed to determine whether early
that play major roles in the development of detection of depression coupled with early
negative cardiac outcomes. There are several intervention can prevent the development of
known behavioral risk factors (e.g., sedentary cardiac disease or reduce the risk for inci-
life style, smoking, high-fat dietary intake) dent of negative cardiac events. Another
among depressed individuals that may con- research priority is to elucidate the poten-
tribute to the development of cardiac disease. tial mediating factors related to depression,
in addition, recent research findings suggest such as failure to comply with medical care,
that several biomarkers are implicated in both sedentary life style, eating habits and smok-
depression and cardiac disease pathogenesis. ing. Also, biological studies are needed to
First, research showed that the hypothalamic– quantify the latent effect of the alterations
pituitary–adrenocortical axis is activated in the level of risk biomarkers (e.g., homo-
during depression, which increases sym- cysteine, iL-6, tumor necrosis factor α, iL-2,
pathoadrenal activity. Consequently, some serotonin, dopamine, cortisol, heart rate
risk markers such as catecholamines, cortisol, variability, and platelet activation), which
and serotonin are elevated in both depression could have negative effect on cardiac func-
and some cardiac diseases. Second, depressed tion. Moreover, depression seems to be more
patients are at increased risk for rhythm dis- of a problem for women with cardiac dis-
orders. Recent evidence indicates that cardiac ease than for men. Therefore, future studies
patients who are depressed exhibit reduced are needed that focus on whether there is
heart rate variability, a known risk factor for indeed a disproportionate weight of comor-
sudden death in patients with CVD (Carney bid depression and cardiac outcomes among
et al., 1995). Third, depressed patients are women.
more likely to have platelet dysfunction that Designing large-scale clinical trials that
may have negative impact on the develop- test biobehavioral research models along
ment and prognosis of cardiovascular dis- with considering both physiologic and
ease such as atherosclerosis, acute coronary behavioral outcomes is essential to a better
syndromes, and thrombosis. Finally, the understanding of the depression–cardiac
research demonstrated a close relationship disease communication. in addition, stud-
among proinflammatory cytokines such as ies designed to develop a more clear account
interleukin-6 (iL-6), tumor necrosis factor α, of psychosocial risk factors to cardiac dis-
depression, and incident of negative cardiac ease are urgently needed. Finally, in an era
outcomes. Briefly, any single mechanism will of genetic research, identifying genes or
fall short of capturing the underlying patho- gene expression mechanisms that may link
genesis processes of depression and cardiac depression and cardiac disease may pave the
disease. Therefore, several mechanisms are path for ultimate understanding of the link
needed to account for the development and between depression and cardiovascular dis-
progression of the two. eases. Studies of effectiveness of depression-
This overview from biopsychosocial specific interventions that address the need
perspective reveals that there is sufficient to improve mood status in cardiac patients
evidence to support an important asso- are relevant to clinical nursing practice and
ciation between depression and cardiac research.
disease. it also suggests a number of signif-
icant directions for future research. Genetic Ali Salman
studies to establish the cellular basis and to Yi-Hui Lee