24 Psychoneuroimmunology

Question 1

What is the main organ of the immune system?

Answer 1

The white blood cells themselves

Question 2

When an immune cell detects something is wrong it releases messenger molecules, generally called…

Answer 2

Cytokines - these include interleukins, prostoglandins yada yada

Question 3

How can it be demonstrated that mental health affects immune response?

Answer 3

Higher rates of illness in patients with mental health issues.

Cancer death rates 39% in depressed patients
50% higher risk of cancer in SZ

Question 4

What did Ader & Cohen (1975) demonstrate about immune suppression?

Answer 4

Immune response can be conditioned -> placebo effect. Brain can suppress immune function.

First paired saccharine CS with immune-suppressant drug cyclophosphamide

Then saccharine alone was able to suppress immune system.

Question 5

How can conditioned immune suppression enable tissue transplant?

Answer 5

If immune suppression is conditioned –with anti-tissue-rejection drug cyclosporine A –it takes longer for body to reject tissue grafts.

Question 6

What evidence is there that immune stimulation can also be conditioned?

Answer 6

Administration of allergenic substance (bovine serum albumin (BSA)) was paired with sprays of almond essence in guinea pigs. After repeated trials, almond essence alone was capable of inducing allergic response. Creation of psychogenic illness.

Question 7

What is the immune effect of cortisol?

Answer 7

Massive immuno-suppressant effect, may be responsible for immune response in lab tests

Question 8

How does stress cause immune response?

Answer 8

Under stress, brain increases production of glutocorticoids (such as cortisol), which has suppressant function on immune response

Question 9

How does the sympathetic and parasympathetic nervous system affect immune response?

Answer 9

NTs released by the SNS and PNS are mainly catecholamines –adrenaline, noradrenaline –and immune cells have receptors for these NTs. Thus the autonomic nervous system can regulate immune response.

Question 10

What is neurogenic inflammation?

Answer 10

Peripheral nerves can release substances from their tips - such as substance P from pain sensory nerves - that can cause inflammation

Question 11

What are the 3 main ways the brain can tune the immune response?

Answer 11

1. Release hormones through the pituitary and other glands
2. Autonomic nervous system can suppress or increase the activity of immune cells in the periphery
3. Pain sensory nerves themselves have neurogenic effect on inflammatory processes in tissue

Question 12

What relation did Cohen et al. 1991 between stress levels and infectious illnesses in people?

Answer 12

Strong linear relationship

Question 13

How does cortisol reactivity (how much cortisol you release when stressed) predict probability of getting a cold?

Answer 13

If few negative life events, little difference between low-and high-cortisol-reactive people;

If many negative life events, high-cortisol-reactive people have drastically higher likelihood of having a cold

Question 14

What changes in physiology do cytokines bring about when you’re sick?

Answer 14

Change blood pressure - how much getting to tissues, quantity of iron in blood, more local inflammation… range of things to help body get rid ofbacteria or viruses

Question 15

What relationship is there between stimulation of immune system and the central nervous system?

Answer 15

An immune response stimulates glutocorticoid response from the central nervous system. It also stimulates sympathetic activation resulting in fever.

Question 16

What is characteristic cluster of symptoms for sick people?

Answer 16

Loss of appetite - anorexic effect
Loss in body weight - anorexic effect
Increase in body temperature 
Tendency to conserve heat
Reduce amount of exploration
Sleep more
Cognitive impairment - can't think straight
Affective changes - anhedonia, depressed, stressed

Question 17

What is the cytokine theory of depression?

Answer 17

Given that immune response produces such similar symptoms to depression, there may be etiological link between the two

Question 18

How does the CNS detect immune activity?

Answer 18

Detection of cytokines by peripheral nerves such as the vagal nerve

Diffusion of cytokines from immune cells into the CNS

Production of cytokines in the brain in response to non-immune danger signals

Question 19

How can brain produce immune response without infection?

Answer 19

In response to danger signals - threat, stress - brain itself will start releasing cytokines which give rise to behavioural and endocrine responses - sleepiness, fever, depression, anorexia etc.

Question 20

Why do we have immune responses?

Answer 20

Sickness behaviours are adaptive:

1. Heat/energy conservation
   - fevers help recuperation
   - more resources for immune cells
2. Minimising harm - stay in bed

Question 21

Why is sickness response like hunger and thirst?

Answer 21

The sickness response amounts to an adaptive motivational state - organises an individual to look after themselves

Question 22

What did Dantzer et al. 2002 study of mother rats demonstrate about motivational state of sickness?

Answer 22

If low ambient temperature, mother will rebuild nest for pups when sick

If high ambient temperature, mother will not rebuild nest for pups

Sickness as motivational state organises behaviour differently according to context

Question 23

How does behaviour contribute to health? 3 things

Answer 23

1. Recuperation from acute injury or infection
2. Prevention of future injury/infection:
   - hygiene (personal and public)
   - lifestyle and diet
   - utilising health services
3. Many diseases require behavioural interventions as part of the cure - obesity, alcoholism etc.

Question 24

In what way are many of society’s health problems psychological?

Answer 24

Metabolic diseases - obesity, diabetes - are actually psych problems - problems caused by behaviour. Best treatment is psychological intervention. GPs do this – “exercise more!” – but don’t follow up.

Question 25

What are the effects of exercise on health?

Answer 25

Reduces:
metabolic diseases
chronic pain
depression
anxiety
cognitive impairments due to aging (eg. Alzheimer's)

Improves recovery for cancer treatment - more likely to survive 5 years after cancer treatment

Question 26

How does exercise affect stress reactivity?

Answer 26

Switches people from high-cortisol reactivity to low-cortisol reactivity. Has regulatory effects on endocrine system.

Question 27

Does having a positive attitude speed recovery from disease?

Answer 27

No. People with positive attitude are less likely to seek help. Pop psych can undermine contemporary medicine.

Question 28

What can a positive attitude to do help?

Answer 28

If you’re dying it improves quality of life. So useful in palliative context.