19. Psychoneuroimmunology Flashcards
The biopsychosocial model of psychoneuroimmunology
What is psychoneuroimmunology?
links between emotions and health were part of pre-modern thought
– e.g. humoural medicine
classic early study found decreased phagocyte activity in response to stress (Ishigami, 1919)
substantial empirical evidence to demonstrate and explain links between psychological states and immune function
links between immunity (PNI) and endocrinology (PNE)
increasing evidence of pathogenic involvement in diseases not previously thought to involve infection and inflammatory processes
General adaptation syndrome
General Adaptation Syndrome consists of 3 phases:
- alarm
- resistance
- exhaustion
Problem with general adaptation syndrome
Most problems we face now are psychological and cognitive but we try to fight it off with a physical stress response
Is stress good or bad?
Both
Short exposure is good because you get bout of energy which boosts immune system
Long exposure is bad because body gets exhausted, and cortisol production goes up, so immune performance goes down for long period of time
Why is prolonged stress harmful?
allostatic load (McEwen & Stellar, 1993)
allostasis = body actively copes with stress by trying to find a new balance
- if stress is prolonged, allostatic load accumulates
- allostatic load refers to the physiological costs of prolonged
- exposure to fluctuating or elevated neural or endocrine responses
that which protects in the short term (acute) can harm in the long term (chronic)
Measures of allostatic load
- decreased cell-mediated immunity
- inability to shut off cortisol in response to stress
What is stress?
stress is a negative experience accompanied by predictable changes aimed at altering the stressful event and/or accommodating its effects :
- biochemical
- cognitive
- physiological
- behavioural
is stress the same in animals and humans?
stress is a response to a stressor - appraisal of the stressor is important
e.g. among school children, cortisol levels were generally higher on test days, but they were highest in some children
Transactional model
Stressor
Primary appraisal: how is the stressor perceived? good/bad?
Secondary appraisal: can i handle it or can I ask for help with it? (social aspect to it too)
If not prepared enough then get STRESS
Perception/expectation and experience
high amounts of stress and the perception that stress harms health are both associated with poor health and mental health.
individuals who perceived that stress affects their health and reported a large amount of stress had a significantly increased risk of premature death
Reactivity to stress
people vary in their reactivity to stress
- reactivity refers to the magnitude of autonomic, neuroendocrine, and immune responses to stress
higher physiological reactivity is related to worse health outcomes in response to prolonged stress (Boyce et al., 1995) - allostatic load
reactivity may vary depending on the nature of the stressor/stress (Smith et al., 1998)
sex differences in reactivity and reactivity to different stressors
Coping
actions people take to reduce stress.
= processes used to manage perceived discrepancies
between the demands of a situation and their perceived resources
not all coping responses are directed toward solving a problem
2 main types = emotion-focused and problem-focused
Emotion-focused coping
behavioural - e.g. alcohol/drug use, seeking emotional support from friends, engaging in activities that distract attention from the stressful situation (e.g. watching TV)
cognitive - e.g. thinking differently about stressful situations (e.g. I’m better off without him; this experience has helped me to re-evaluate my goals/values)
We tend to use emotion-focused in uncontrollable situations - death of loved one
Problem-focused coping
- e.g. devising (and sticking to) a study schedule, negotiating an extension on bill payment
We tend to use problem-focused coping for situations that are more controllable
Responses to stress can moderate its effects on immune function
different coping interventions:
expressive writing emotions
- emotional disclosure enhances mood, immune function, and health
relaxation / self-hypnosis / guided imagery emotions
self-hypnosis / guided imagery
- may mute effects of stress on immune system
problem solving and stress management problem + emotions
- can reduce effects of stress on immune function
physical activity
- can reduce effects of stress on cortisol (Pauly et al., 2019)
Social support
direct effects
- via psychosocial influences on endocrine and immune function - i.e. people feel less stressed
indirect effects
- people with better social support are more likely to adhere to medication and more likely to use health services
Depression and immunity
negative emotions - loneliness, pessimism, depression - impair immune function
= greater susceptibility to infections
= slower wound healing
= altered immune function
- reduced number and function of lymphocytes
- reduced number and function of NK cells
- changes in pro-inflammatory cytokines
- increases in interleukin-6 (mediator of fever + inflammation)
‘dose-response’ effect - more severe depression is related to greater immune effects
Effects of depression
depression linked to more rapid progression of diseases: HIV/AIDS and cancer
effects of depression may be
- direct: effect on immune function
- indirect: unhealthy behaviour / lower adherence
psychological interventions to treat depression can lead to improved immune function
Positive mood and immunity
increasing evidence that positive moods and personalities are related to enhanced immune function
personality - [hard to modfify]
optimism, emotional expressiveness, extraversion associated with: NK cell cytotoxicity; proliferation of helper T lymphocytes
mood [modifiable]
watching comedy videos leads to increases in immune function
positive events and moods may have longer-lasting effects on immune function than negative events
implications for interventions
