that following a cancer diagnosis, as many as half of those who smoked quit (Gritz et al., 2006). The concept of “teachable moments” has been used to explain how, after experiencing health events such as serious illness, people are motivated to take up health-promoting behaviors (McBride et al., 2003; Demark-Wahnefried et al., 2005).

Over the course of many serious acute and chronic conditions, however, patients’ adherence to health professionals’ recommendations for improved health can be quite low. And despite motivation, changes in actual health behaviors do not always come about or persist. For example, dozens of studies have found more than 30 percent nonadherence to dialysis, dietary and fluid restrictions, and transplant management in patients with end-stage renal disease, diabetes, and lung disease. In patients with cardiovascular disease, nonadherence to lifestyle changes, cardiac rehabilitation, and medication regimens is almost 25 percent. In patients with HIV, nonadherence to highly active antiretroviral treatment regimens and behavior change is 11.7 percent (DiMatteo, 2004). Similar rates of nonadherence have been observed in cancer patients despite the importance to survival and better health care outcomes of adhering to a treatment regimen. More than 20 percent of cancer patients have been found to be nonadherent to a variety of treatments, including oral ambulatory chemotherapy, radiation treatment, and adjuvant therapy with tamoxifen (Partridge et al., 2003; DiMatteo, 2004). For adjuvant tamoxifen, for example, adherence can be as low as 50 percent after 4 years of treatment (Partridge et al., 2003). One study of the natural progression of exercise participation after a diagnosis of breast cancer found that women did not significantly increase their levels of exercise over time and were in fact exercising below recommended levels despite their expressed intentions otherwise (Pinto et al., 2002). As discussed below, depression and other adverse psychological states can thwart adherence to treatment regimens and behavior change in a number of ways, for example, by impairing cognition, weakening motivation, and decreasing coping abilities.

Impaired Cognition

To achieve healthy lifestyles and manage chronic illness effectively, patients must first understand what they need to do to care for themselves. The necessary information may come from many sources, including the media, family members, and health professionals, and may include, for example, reasons for needed chemotherapy, the exact ways in which medication should be administered, and the importance of sleep and a good diet. Distressed psychological states can seriously challenge the cognitive functioning and information processing required to understand treatments and organize health behaviors. Stress, anxiety, anger, and depression can

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