Lecture 14 - PNI Part 2

Question 1

what is Stress:

Answer 1

adverse condition in which the demands of a situation are perceived to be greater than our ability to cope with them

Question 2

explain Short-Term Stress and nervous system and immune system interactions

Answer 2

Nervous system and immune
system interact closely
ì HPA Axis – adaptive
ì Fight-or-Flight mode
ì Cortisol mobilizes energy, heart beat, blood flow (for running)
ì When stressor is gone, signaling quiets down and cortisol levels return to normal

Question 3

explain Acute Stress: Typical Lab PNI Study

Answer 3

ì acute, short-term stressors (e.g. making speeches, Cohen)
ì immune functioning measured
ì exposure to antigens (e.g. virus)
ì record illness occurrences

Question 4

what is Long-Term Stress

Answer 4

When stress is ongoing or severe, cortisol gets chronically overproduced. HPA axis eventually becomes desensitized to the negative feedback telling it to “calm down

Question 5

what is the HPA-Axis reaction to long term stress

Answer 5

Dysfunction
E.g. adrenal glands so depleted that they are unable to release or
produce cortisol
ì Tired, irritability, depression, anxiety, weight loss, etc. ì Lowered immune function (more infections etc.)

aka becomes desensitizes

Question 6

is long or short term stress worse for people

Answer 6

ì Long-term stress
ì strong or chronic stressors –> significantly
more illness over time
ì even when controlling for third variables
ì immune system can remain suppressed in the long term

Question 7

Effect of Stress on Immune Function: (Kiecolt-Glaser et al., 1996)

Answer 7

impaires vaccine responses

Question 8

explain the Link between receiving social support and immune functioning

Answer 8

ì This link is especially strong for older adults
ì Supported by studies showing that social support predicts greater NK cell activity
ì Suggest that loneliness is a risk factor for poor antibody response to influenza vaccination
ì Studies of newly separated or divorced showed that these life events can negatively impact immunity

Question 9

Implications for Serious Immune Diseases?

Answer 9

HIV and stress: Leserman et al. (1997)
Link with chronic stress:
• Faster progression to AIDS
• Faster progression of cervical cancer in HIV+
women

Question 10

what are the Methodological Issues in PNI

Answer 10

Several challenges in PNI research
ì Time of measurement after stressor
ì Effects may be different

Many forms of immune-system function
Statistical significance vs. clinical significance ì Is statistical significance clinically important?

Question 11

is there a link between stress and canacer

Answer 11

Role of stress controversial due to
• Diversity of cancers
• Long time frame
• Many confounding factors

Ø No reliable empirical support in humans
Ø Only epidemiological or observational research
findings
Issue of “blaming the victim”

Question 12

Can Stress CAUSE Cancer? Hypothesized Mechanisms

Answer 12

NK cells protect against cancer
ì Stress affects endocrine system, which affects NK cell
activity
ì NK cell activity crucial in fighting cancer cells
ì No experimental findings in humans (ethically not possible)

Maybe: Stress can worsen cancer but not predispose someone to developing cancer?
ì Limited observational support
ì Implication: stress reduction may improve immune response and slow cancer progression (no clear evidence)

Question 13

explain the link between Social Support and Cancer

Answer 13

For cancer patients, social support:
ì Improves immunologic responses
ì Improves psychological adjustment
ì Can help the patient deal with intrusive thoughts about the cancer and improve psychological adjustment (Lewis et al., 2001)
ì But can be problematic:
ì Because it tends to significantly drop off even within the first year after diagnosis (Arora, Finney Rutten, Gustafson, Moser, & Hawkins, 2007)

Question 14

explain Interventions for Chemotherapy

Answer 14

One common cancer-related problem are the side effects associated with chemotherapy, particularly fatigue
ì Interventions designed to target these side effects can significantly improve quality of life
ì Such interventions include: ì Relaxation
ì Expressive disclosure
ì E.g., writing about benefits derived from cancer
ì Dragon boat racing
ì Mindfulness-based stress reduction

Question 15

Summary

Answer 15

ì PNI is the study of the interaction between psychological processes and the nervous and immune systems of the human body
ì Stress affects the ability of the body to fight foreign invaders
ì Social support and other resources can buffer the negative effects of stress on immune system functioning
ì No clear evidence on stress leading to cancer or stress management increasing length of survival