to stress) and immune system response (Brannon &
Feist, 2010). Currently, it remains unclear whether
immunosuppression is a direct effect of stress or
whether it is simply part of the body’s response to
stressful events (Brannon & Feist, 2010). In any case,
stress does appear to be an important (though not the
only) influence on health and illness.
Behavior and Health. Behaviors, habits, and life-
styles can affect both health and disease. Everything
from smoking, excessive drinking, or poor diet to
deficient hygiene practices have been implicated.
Such behaviors are often deeply rooted in cultural
values or personal needs and expectations. In any
event, they are not easily changed. Later in this
chapter, we will discuss in more detail several beha-
viors or lifestyle choices that have been linked to
health. These include cigarette smoking, alcohol
abuse and dependence, and weight control.
Cognitive variables may influence our decisions
about adopting healthy or unhealthy behaviors
(Bandura, 2001). To cite one example, many health
psychologists have focused on the variable self-
efficacy. Self-efficacy, discussed in earlier chapters,
refers to“people’s beliefs about their capabilities
to exercise control over events that affect their lives”
(Bandura, 1989, p. 1175). Self-efficacy is relevant to a
number of topics addressed by health psychologists,
including major theories of health-related behavior
change. This construct plays a major role in the most
prominent social cognitive models of health behavior,
including the health belief model (Rosenstock, 1974;
Rosenstock, Strecher, & Becker, 1988), protection
motivation theory (R. W. Rogers, 1975; Sturges &
Rogers, 1996), and the theory of planned behavior
(Ajzen, 1985, 1988).
Protection motivation theory(PMT), for example,
posits that behavior is a function ofthreat appraisal
(an evaluation of factors that will affect the likeli-
hood of engaging in the behavior, such as perceived
vulnerability and perceived potential for harm) and
coping appraisal(an evaluation of one’s ability to
avoid or cope with negative outcome). Coping
appraisal is influenced by one’s self-efficacy, or
belief that one can implement the appropriate cop-
ing behavior or strategy (Maddux et al., 1995).
An example that applies PMT to a real-life
health decision may be instructive. Janey, an adoles-
cent girl, faced a decision about whether or not to
start smoking cigarettes because she would like to
lose weight. According to PMT, Janey would
engage in threat appraisal and coping appraisal.
Threat appraisal might involve evaluating the dan-
gers of smoking (e.g., lung cancer) as well as the
likelihood of her own vulnerability to this outcome.
To the extent that she does not perceive the danger
to be severe or immediate to herself, Janey might be
more likely to start smoking. Coping appraisal is also
relevant. This process might involve Janey’sevalua-
tion of how likely she could refrain from smoking
(the recommended coping strategy). To the extent
that Janey believes she will not be able to refrain
from smoking (e.g., because all her friends smoke
and she would like to lose weight), it becomes
more likely that she will engage in this behavior.
Thus, the cognitive variable self-efficacy can play a
prominent role in behavior and lifestyle choices that
ultimately influence health.
Problems can also arise from the ways in which
people respond to illness. Some people may be
unable or unwilling to appreciate the severity of
their illness and fail to seek timely medical help.
When they do get medical advice, they may fail
to heed it. Among youth, decisions become more
complex, as both the perceptions of the youth and
their caregivers influence health behavior decisions.
All of these behaviors can indirectly foster adverse
outcomes. We will discuss medical treatment com-
pliance later in this chapter.Personality Factors. Both directly and indirectly,
personality characteristics can affect health and ill-
ness in many ways (Smith & MacKenzie, 2006; Suls
& Bunde, 2005). For example, (a) personality fea-
tures may result from disease processes; (b) person-
ality features may lead to unhealthy behaviors;
(c) personality may directly affect disease through
physiological mechanisms; (d) a third, underlying
biological variable may relate to both personality
and disease; and (e) several causes and feedback
loops may affect the relationship between personal-
ity and disease.492 CHAPTER 17