a diagnosis of cancer were at the highest risk of developing symptoms of depression within 2 years (13 percent incidence), with more than triple the risk of all others combined (Polsky et al., 2005). (Those with a diagnosis of chronic lung disease, heart disease, and stroke also had higher-than-average rates of depressive symptoms.)
Depressed or anxious individuals with a variety of comorbid general medical illnesses (including cancer) report lower social functioning, more disability, and greater overall functional impairment than patients without depression or anxiety (Katon, 2003). Distressed emotional states also often generate additional somatic problems, such as sleep difficulties, fatigue, and pain (Spitzer et al., 1995; APA, 2000), which can confound the diagnosis and treatment of physical symptoms. Among patients with a variety of chronic medical conditions other than cancer, those with depressive and anxiety disorders have significantly more medically unexplained symptoms than those without depression and anxiety, even when severity of illness is controlled for. Patients with depressive and anxiety disorders also have greater difficulty learning to live with chronic symptoms such as pain or fatigue; data suggest that depression and anxiety are associated with heightened awareness of such physical symptoms. Multiple studies of patients with major depression have also found higher-than-normal rates of unhealthy behaviors such as smoking, sedentary lifestyle, and overeating (Katon, 2003). Depression is associated as well with poor adherence to prescribed treatment regimens (DiMatteo et al., 2000).
Impaired Adherence to Medical Regimens and Behavior Changes Designed to Improve Health
While serious health events can trigger health-damaging behaviors—such as use of substances and consumption of unhealthful foods—as individuals cope with the distress associated with the illness, they can also motivate people to take up a number of health-promoting behaviors (McBride et al., 2003; Demark-Wahnefried et al., 2005). One study, for example, found that 6 months after surviving a heart attack, 17 percent of patients were engaged in four health-promoting behaviors (refraining from smoking, weight reduction, sufficient physical activity, and consumption of a low-fat diet), compared with just 3 percent of patients at baseline (Salamonson et al., 2007). Another study found that following HIV diagnosis, 43 percent of individuals reported increased physical activity and 59 percent improved diet (Collins et al., 2001). In general, research indicates that following a cancer diagnosis, many patients engage in behaviors such as stress management, quitting smoking, aerobic exercise, and major dietary change (Blanchard et al., 2003; Ornish et al., 2005; Andrykowski et al., 2006; Rabin and Pinto, 2006; Humpel et al., 2007). One study found