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Psychoneuroimmunology

6 important questions on Psychoneuroimmunology

HPA (Hypothalamic-pituitary-adrenal axis)

After activation SAM:
- HPA axis becoms activated
- provides additional energy resources
- initiated in hypothalamus
- when activated corticotrophin-releasing hormone (CRH) is released from the paraventricular nucleas of the hypothalamus
- this stimulates release of adrenocorticotropin hormone (ACTH) (through blood)
- culminating in relaease of glucocorticoids (cortisol) from adrenal cortex (metabolism, glucose storage, learning and memory)

Effect of stress hormones (cortisol)

Cortisol:
- stimulates lymphocyte maturation (+)
- regulates inflammatory responses
- promotes catechalomine (norepinephrine/ epinephrine) release (+)
- suppresses SAM system, thereby regulating the stress response (-)

When survival is not htreatened can lead to poor immune functioning.

Clinical relevance; wound healing

Mice placed under restraint stress have shwn higher glucocorticoid secretion, less inflammation, impaired bacterial clearance and slower healing compared to other mice.

Brief naturalistic stress has been associated with slower healing.
Research has also shown that anger and depression can influence healing.

Clinical relevance; heart disease

There is increasing evidence that psychological factors influence the development and progression of heart disease.

The immunological pathway involved is unknown.

* chronic psychological factors
Chronic stress or a hostile personality type --> encourages artherosclerosis (build of plaque)

* episodic psychological factors
Depression --> destabilises artherosclerotic plaques through activation of ACTH pathway

* acute psychological factors
Anger outbursts --> cardiac ischaemia and acute coronary syndromes by promoting the rupture (scheuring) of plaquest

Clinical relevance; optimism

- Optimism is positively correlated with cellular immunity in controllable, brief and straighforward situations
- Optimism is negatively correlated with cellular immunity in uncontrollable, chronic and complex situations
- the latter may derive from optimists' conscientiousness and over-engagement in tasks, even if complex, they cannot 'give up'

PNI to improve health outcomes

Psychological interventions
-->
decreasing negative mood states
-->
decreases in SNS and hormonal activation
-->
regulating immune processes

emotional disclosurediscussing personal issues, by labelling the problem and discussing causes and consequences

CBT and psychotherapyCognitive behavioural therapy (CBT) and psychotherapy have been applied in several clinical groups to alleviate distress of medical treatments and prevent disease progression

relaxation and exercisehas generated positive immune benefits in non-patient populations. Improves immune responses in older persons, as old age tends to make us more susceptible to infections.