The results of the study showed that complete wound healing took an average of 9
days or 24 per cent longer in the caregiver group compared to the controls. They also
found differences between the groups in the production of an important cytokine
(interleukin-1ß) suggesting this as one of the immunological mechanisms underlying
the observed effects.
Next this research group investigated whether a relatively minor, commonplace
stressful event such as an examination had the potential to similarly influence wound
healing. In this study, Marucha, Kiecolt-Glaser and Favagehi (1998) placed a 3.5 mm
punch biopsy wound in the mouths (i.e. on the hard palate) of a sample of dental
students, once during the summer vacation and again 3 days before a major
examination. This repeated measures design allowed the participants to act as their own
controls. Again, two independent methods assessed wound healing (daily photographs
and a foaming response to hydrogen peroxide). Surprisingly, all students took longer
to heal in the examination conditions compared to control conditions with complete
healing taking an average of 3 days (or 40 per cent) longer in the examination
condition. These data suggest that even short-lived, predictable and relatively benign
stressors can have significant consequences for wound healing. More importantly, these
findings have important implications for understanding recovery from surgery.
Evidence suggests that a more negative psychological response to surgery is associated
with a slower and more complicated post-operative recovery, greater pain, longer
hospital stay and worse treatment adherence (for more detailed discussion see Kiecolt-
Glaser et al., 1998). Moreover, these results indicate that if patients are psychologically
better prepared for surgery they are likely to experience significant health benefits. This
is consistent with a recent investigation of recovery from total knee replacement surgery
that showed that higher levels of anxiety and depression pre-operatively were associated
with poorer recovery one year later (Hanusch et al., 2014).
Psychological influences on recovery from surgery
Using this work as a starting point, Kiecolt-Glaser and colleagues (1998: 1209) have
developed a model of psychological influences on surgical recovery. They suggest that
psychological factors can impact wound healing, a key variable in short-term post
surgical recovery, via three key pathways:
1 Emotions have direct effects on ‘stress’ hormones and they can modulate immune
function.
2 The patient’s emotional response to surgery can influence the type and amount
of anaesthetic and anaesthetics vary in their effects on the immune and endocrine
system.
3 Individuals who are more anxious are also more likely to experience greater post-
surgical pain and pain can suppress immune functioning.
SUMMARY
In this chapter we have considered several of the key psychophysiological pathways
through which psychological factors (and particularly stress) may influence health and
36 BIOLOGICAL BASES OF HEALTH AND ILLNESS