Depression and Cancer

In many studies there has been little differentiation between the effects of stress and depression on immune functioning, and subsequently the development of cancer or poor prognosis for recovery from cancer. A variety of data suggests that depression or stress may precipitate important biological effects (Anderson, Kiecolt-Glaser & Glaser, 1994), including those influencing the autonomic, endocrine, and immune systems. "Stress may be routed to the immune system by the central nervous system (CNS) by activation of the sympathetic nervous system (adrenergic nerves terminating in the lymphoid organs) or through the neuroendocrine-immune pathways. In the latter case, a variety of hormones released under stress have been implicated in immune modulation" (p.5-6).

And in considering the role of depression in the tentatively established relationship between social support and immunity (Spiegel, 1996), it has been proposed (Baron, Cutrona, Hicklin, Russell & Lubaroff, 1990) that depression may have a major role as a mediating variable in this relationship. "Depression (especially during times of stress) may elevate the release of corticosteroids and catecholamines, substances known to produce immunosuppression. Consistent with this view, depression has been directly associated with impaired immunological functioning in several studies. As a result, it seems possible that social support may have its effect on immunity primarily by alleviating or preventing depression, thereby damping the release of corticosteroids and catecholamines " (p. 3).

Musselman (1996) reviewed data comparing depressed cancer patients with nondepressed cancer patients and found that some patients with major depression had an inability to suppress the high amounts of cortisol produced by their adrenal glands. This abnormality was found using the dexamethasone suppression test in which 1 mg of this synthetic glucocorticoid was administered to the patient at 11 p.m.. Samples for measurement of cortisol concentrations were obtained at 4 p.m. and 11 p.m. the next day. "Normally, the elevated synthetic glucocorticoids will down-regulate the cascade of events that culminates in stimulation of the adrenal glands. One-half to two-thirds of depressed patients, however, exhibited dexamethasone nonsuppression" (p. 260).

However, the relationships between cancer, depression and the various physiological systems of the body are complex, cybernetic systems ,not amenable to direct causal analysis. Although correlations have been established between immunosuppression, cancer and depression, it may be rather impossible to determine the originating factors in most research studies. Depression may be a result or a precipitating factor. Quigly (2000) considered that treatments for breast cancer that have a disrupting effect on estrogen levels may increase patient’s risk of developing depression. "Estrogen insufficiency might be a critical factor in the tendency for chemotherapy to precipitate a persistent major depressive disorder" (p. 1). Once again, although correlations have been established between stress, depression, immunosuppression and cancer, correlations do not establish causality.

Information and webpage by Paul Susic  MA Licensed Psychologist   Ph.D. Candidate  (Health and Geriatric Psychologist

References 

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