- Created by: Liah Zusman
- Created on: 04-04-12 09:12
Symptoms of stress
- dry mouth
- increase temperature
- frequent use of wc
- hair loss
- pulling hair
- loss of appetite
causes of stress
- new school
- new job
- new house
- unrealistic time constraints
- high expectations
- financial problems
- chronic illness
physiology of the stress response
ANS- 1. pituitary gland 2. endocrine system 3. adrenal gland
The 2 systems come together in their action on the adrenal gland
Adrenal gland- has 2 sections. 1.adrenal medulla 2.adrenal cortex
Both release hormones- diff sets into blood stream
Adrenal cortex controlled by the pituitary gland which lies in the skull cavity just below the surface of the brain.
The master gland releases ACTH (adrenocorticotrophic hormone) which stimulates release of Corticosteroid Hormones
there are 2 groups of corticosteroids: 1. GLUCOCORTICOIDS and MINERALCORTICOIDS
The pituitary is directly connected to the part of the brain called the hypothalamus. This can alter levels of pituitary hormones in the bloodstream.
physiology of the stress response continue
The ANS & the adrenal medulla.
The role of the ANS is to maintain the normal functioning of the heart, digestive system, circulatory system & various glands including the ADRENAL MEDULLA.
ANS has 2 subdivisions:
SYMPATHETIC (bodily arousal, heart rates & bp increase, fats & carbs are mobilized, digestion slow down) & AND PARASYMPATHETIC - relaxed... opposite.
The adrenal medulla is controlled by the ANS and the sympathetic activation stimulates the release of adrenaline and noradrenaline into blood stream.
Adrenaline is well known as an arousal hormone and nora adrenaline has similar effects. Together the reinforce the pattern of sympathetic activation, stimulating th heart rate & bp & mobilzing energy reserves
Parasympathetic and sympathetic
PARASYMPATHETIC- normal SYMPATHETIC- stress
pupil - constricted pupil- dilated
saliva- stimulated saliva- inhibited
heart-slowed heart- accelerated
airways- constricted airways- dilated
stomach-stimulated stomach- inhibited
bladder- contracted bladder- relaxed
- term introduced to ps from mechanical engineering where tension on metal by heavy loads
- Selye in the 1930/40's carried out work with rats, giving rats injections. 1st with saline and noticed the rats developed ulcers in their stomach (gastric)/ he than began to wonder what caused it. By comparing 2 groups of rats, 1 injected with saline other water, he released both groups developed the ulcers so it must be the injection itself causing the condition!
- Cox and Mackay 1978 and Lazarus and Folkman 1985 emphasises individual differences. A. person's perception on themselves & the world. B. key process of appraisal C. primary & secondary appraisal e.g phobias
the transactional model of stress
Actual coping ability Actual demands
Perceived coping ability Perceived demands
Mismatch between demands & coping ability
GO TO GO TO
feelings of stress bodily stress response
Primary & secondary appraisals are based on our perceptions of ourselves and the world around us, when we put these 2 things together it can lead to a definition of stress.
Stress is when there is an unbalance/ discrepancy that exists between the perceived demands and perceived coping resources.
The advantage of the model is that it takes into account individ differences, the model itself shifts the focus from the actual demands and coping resources to individual's perceived views.
Selye ignored individ diffs but through his work promoted studies into stressors.
The effects of stress are not limited to just physiological factors but also to emotions such as anxiety & depression and behaviour to cope with the situation.
Bodily's response so stress
There are highly specialised symptoms, involved in the bodily's response to stress, all of which are coordinated by the brain
there are billions of these, organised in tissue and cells, throughout the body and they are covered in complex membranes of several layers. Which allows conduct of electrical impulses. The electrical activity is known as action potentials (technical term of nerve impluses, pulses of electrical activity conducted along the neuron, action potentials represent coding of information in the nervous system)
Dendrites are where a nerve impulse begins and than travels across the cell. The nerve impulses travel along the axon on a motor neuron.
All aspects of human behaviour: perception, memory, language, personality etc. are all coded by patterns of nerve impulses in different parts of the nervous stem. There are between 15-100 billion neurons in the brain.
Neurons are not physically connected to one and another. Between the axon termnial and the next neuron is a tiny gap, the synapse, visible only under an electron microscope. Although tiny, this gap presents an obstacle to the nerve impulses as it cannot jump across/
Transmission of nerve impulses across the synapse is chemical.Stored within the axon/ presnaptic terminal are packets of chemicals known as neurotransmitters. As nerve impulses travelling down the axon reach the axon terminal they stimulate the release of neurotransmitter molecules that can diffuse over to the postsynaptic membrane of the following neuron. Located on this membrane are synaptic receptors.
As the neurotransmitter molecule reaches the post synaptic membrane it bind the receptor for a brief period of time. This combination of neurotransmitter with receptor alters the biochemical characteristics of the postsnyaptic membrane; more like;y to be triggered at the point of the membrane.
it is a feature of the nerve impulse that is an all-or-none principle; either it occurs or it doesn't. for a nerve impulse to be triggered on the postsynaptic membrane sufficient neurotransmitter molecules must be released from the presynaptic terminal. Once triggered, the nerve impulse will be conducted along the postsynaptic neuron, along the axon to the axon terminals, where the process is repeated at the next set of synapses.
Areas of workplace stress
It is considered one of the major sources of stress for many people. there are increasing levels of stress in a variety of jobs, such as nursing, the police force, airline pilots.
This type of stress causes distress to the individual but can lead to:
- poor performance at work
- increased absenteeism
- stress related illness
workplace stress factors
With many people having to balance the competing demands of home & work, in particular parents with small children, this potentially very stressful area has become the subject of much debate. the concept of work-life balance refers to the ideal situation where an individual has time for both work and home responsibilities, leading to less stress and better psychological adjustment.
This has been a central focus of research into workplace stress. the degree of control a person has over their workload has been shown to directly affect the level of stress experienced. High levels of control lead to lower levels of stress, while low levels of control, typically experienced by workers lower down the organisation hierarchy can increase stress.
more workplace stress factors
Heating, lighting and the physical arrangement of the workplace are all potential sources of stress.Many studies have shown that intense noises & increases in temperature can lead to frustration, stress and sometimes aggression. The physical layout of the workplace can affect the psychological well-being of the employee in terms of 'personal space' and privacy.
This one of the most obvious factors, but interestingly research shows that it is not just overloads that can be stressful (Dewe 1992) but having too little can do the same.
study about control
Marmot et al 1997
Aim find out the relationship between workplace stress and health (involves various individual and social risk factors e.g smoking, blood pressure & cholesterol levels, obesity & socioeconomic status)
Procedure P's were taken from London based government civil servants and the studies are called Whitehall studies. Marmot analysed data from over 700 p's on Whithall 2 study p's were followed up over 5 years, all were free of heart problems at the start.
Result Whitehall 1 study clear differences between workers were found regard to heart problems and mortality rates. the data showed similar differences in heart disease to Whitehall study 1 with the rate in lowest grades being 1.5 times the rate high grade.
Conclusion Whitehall 1, workers in lower paid grades had twice the illness rates of high paid workers. Differences in risk factors (e.g. workers in lower tend to smoke more and have higher bp) 1/4 of this differences that risk factors such as smoking, obesity and hypertension could account for some of the increase in lower grades. However the most significant factor was the degree of decision latitude of control p's had.
Evaluation the study was largely based on self report questionnaires which raise issues of biased responding by p's, for instance underestimating risk factors such as smoking. Some factors that were not measures may have contributed to the results. e.g workers in the lower grade may have in common some characteristics that makes vulnerable to heart disease but that was not measured in the study. the sample was of gov civil servants, although males and females were represented, this is otherwise a biased sample and it could be difficult to automatically generalise the results to other groups of workers. however the findings are supported by many other studies that have demonstrated a clear relationship between stress at work and lack of control.
In a v.different workplace Johnson et al 1978 found higher levels of stress hormones and stress related illness in a group of highly skilled southhulll employees whose was machine based.
there is little risk of psychological harm in this type of questionnaire study of workplace stress, although informed consent and debriefing should be routine. Workers developing illnesses should also be provided with the neccesary support.
Measuing and dealing with workplace stress
In addition to all the sources of stress mentioned, there are others:
- role of ambiguity (being unsure of your responsibilities)
- relationships with other colleagues
- career progression
Companies have a variety of questionnaire packages available to asses workplace stress to measure the sources of stress as perceived by employees. These questionnaires measure characteristics such as social support. Type A behaviour and coping strategies. The outcome of such a profile is usually to devise strategies for employees to reduce the negative effects of stress e.g individual health problems, absenteeism, low productivity.
These strategies can include individually tailored schemes e.g change hours work/days, alter environment Workers at all levels can be give more control over the distribution and organisation of their workload.
Measuing and dealing with workplace stress continu
One thing that stands out across all these areas is the role of individual differences- people vary in relation to their vulnerability to stress related problems. they may react to stress differently or different ways of coping with stress and different support systems
The bodily's response to stress 1
- The individual appraises a situation as stressful- possibly involving a threat/ danger/ possibly demanding and in relation to capability might be considered too difficult to manage. The individual evaluates the situation using previous experiences.
- the appraisal involves the cortex of the brain and limbic system and if a stressful situation is identified signals are sent to the HYPOTHALAMUS to activate HPA (hypothalamic - pituitory axis) and SAM (sympathetic adrenal medullary pathway)
- Our thoughts and anxieties can act as demands that perhaps cannot be coped with, this will activate the HYPOTHALAMUS of the body's stress response.
The bodily's response to stress 2
- The HYPOTHALAMUS control 2 major systems that have central roles in the bodily's response to stressors
(diagram) REFER TO PAPER
- The pituitary gland sits beneath the brain. this is the master gland of the body and releases a number of hormones into the bloodstream. it control other glands and its connected to the hypothalamus
The bodily's response to stress 2
- The key hormone released by the gland is ACTH (adrenocorticophic hormone). the hypothalamus stimulates the release, of ACTH into the blood & this hormone travels to the ADRENAL CORTEX part of ADRENAL gland, we have 2 adrenal glands located close to the kidney on each side of the body.
- When ACTH reaches the adrenal cortex it stimulates corticosteriods release. These go into the bloodstream and have major effects on the body.
- The SNS control the internal organs such as the glands, heart & circulatory system & digestive system.
The bodily's response to stress3
- Nerve pathways of the SNS start in the brainstem & travel into the spinal cord & nerves to to the various body organs - one of these runs to the adrenal cortex makes up the adrenal gland. the SNS stimulated the gland to produce adrenaline & noradrenaline into the bloodstream
- the ANS control out internal organs automatically without our conscious control & alter appraisal in the higher brain detecting a stressful situation it instructs the hypothalamus to release ACTH from the pituatory gland.
- The hypothalamus commands the ans to activate the sns resulting in an increase release of noradrenaline & adrenaline
The bodily's response to stress nutshell
- In a nutshell, the perception of a situation produces activation of the HPA and the SAM pathway & a number of hormones flood into the blood. These have no effect on the body but are designed to provide for energy expenditure used in response to stress e.g to escape/ confront
- SNS has direct connections with the heart & activate it to speed up heat rate & raise blood pressure.the release of adrenaline & noradrenaline increase these & sustain them so 02 in the blood is rapidly pumped to the muscles of the skeleton allowing increased physical activity
- The body receives are in the form of glycogen stored in the liver and fat receives in fatty tissue. The corticosteriods now in the bloodstream activate the release of these energy reserves in the form of glucose and fatty acids into the bloodstream.
The bodily's response to stress nutshell 2
- Prolonged activation in the case of prolonged stress means there is a consistent release of fatty acids and this can lead to a build up of deposits in the arteries & if blood flow is made difficult due to the narrowing, it is likely to lead to v.high blood pressure & a possible heart attack. Fuming up of the arteries is called atherosclerosis
- Raised corticosteroids if sustained over a long period of time also the effect of suppressing the body's immune systems - the body's defence system against infection. this is why people under stress are more susceptible ton infection
- The body's response to stress includes activation of HPA and SAM existed in the lives of caveman when stressors might be predators & today even though stress in the modern world is v.different the same activation occurs.
- Cerebrum - highly evolved region of the brain that accounts for many specifically human activities such as languages
- Frontal lobe- essential for consciousness & other higher thought processes as well as the control of emotions & certain kinds of memory
- Cerebeilum- often described as the auto pilot of the brain, coordinates movements without the need of conscious control
- Hypothalamus- involved in secreting hormones & plays an important role in homeostasis- constant regulation of temp & other vital processes.
- Brainstem- evolutionary ancient part of the brain controlling basic bodily functions such as breathing, digestion & blood pressue
The nervous system
the nervous system is made up of 10-12 billion neurones of 3 main types:
- Sensory neurones, which respond to external stimuli such as touch/ light
- Motor neurones, which carry messages to muscles, organs or glands
- Association neurones (most common type), which transmit & integrate info between other neurones
the nervous system 2
the nervous system includes:
- the central nervous system (CNS) which consists of the brain and spinal cord
- the peripheral nervous system (PNS) which consists of 43 pairs of peripheral nerves whose function is to link the senses of CNS and the CNS to the muscles and organs. The PNS functions through 2 main systems:
- the somatic nervous system- this allows communication & voluntary interaction with the outside world via sensory & motor neurones
- autonomic nervous system- connects CNS to internal glands/ organs/ involuntary muscles to regulate internal processes without conscious control. It has 2 branches that interact to govern many aspects of behaviour
------ a. the sympathetic branch- prepares the body for action by increasing heartbeat, breathing, blood sugar levels, & adrenaline release
-------b. the parasympathetic branch- acts to converse and restore body energy when relaxed
the endocrine system
The endocrine glands secrete hormones into the blood stream to affect behaviour.
There are many endocrine glands throughout the body which are regulated by the pitiuitary gland (master gland), which is itself controlled by the hypothalamus of the brain.
Pituitary gland- secretes many hormones from its anterior & posterior sections, e.g growth, maternal care
Pineal gland secretes melatonin involved in regulating body rhytms
Thyroid gland secretes thyroxin whoch effects body metabolism
Adrenal gland secrete corticosteriods involved in muscle development and epinephrine/ norepinphrine involved in activating sympathetic nervous system.
Gonads secrete androgens involved in masculine characteristics (possibly behaviour) & oestrogen & progesterone which regulate the female menstrual cycle.
Stress is related to brain mechanisms which control our reactions to stressful situations. Stress is also related to illness & when the body is under pressure for long periods it will damage the body.
Research supports this & this research comes in many forms in:
- controlled lab experiments
- real-life stressful situations
There are major life stressors & these are indicated in life event scales such as:
- Holmes & rahe 1967- S.R.R.S scale
- Kanner et.al 1981- Hassles scale
- Sarason et.al 1978- Life Events scale
- Lazarus 1978- Uplifts scale
Most people accept a link between stress & illness- it seems common sense that being under pressure for long periods would damage the body in some way
Stress in the workplace has high profile in society & the media leading to ill-health & absenteeism
There are many factors that can influence an individual's response to stress, such as personality
Some people are more vulnerable to stress whilst others are more resistant
There are several specific physiological or psychological methods of coping with stress each with its own advantages & disadvantages
- Hindbrain- division of the brain, containing the medulla, pons & cerebellum
- Forebrain- largest division of the brain, containing the systems controlling higher cognitive & emotional functions: key components are the diencephalon, limbic system, basal ganglia & cortex
- Cerebellum- large structure in the hindbrain, involved in coordination of movement, damage results in a loss motor coordination
- Diencephalons- component of the forebrain, containing the thalamus and hypothalamus
- Thalamus- large structure in the diencephalon of the forebrain- relays sensory input from sensory pathways on the cortex.
- Hypothalamic- Pituitary- Adrenal Axis (HPA)- 1 of the 2 key pathways involved in the body's response to stress. The hyporthalamus stimulates release of adrenocorticotrophic hormone (ACTH) from the pituitary gland into the bloodstream. ACTH travels to the cortex of the adrenal gland and triggers release for cortisol & other corticosteroids in the bloodstream
- Sympathetic- Adrenomedullary Pathway (SAM)- 1 of the 2 key components of the body's response to stress. Activated by the hypothalamus, nerve pathways of the sympathetic branches of the ANS stimulate the adrenal medulla to release adrenaline and noradrenaline in the bloodstream.
These contain the systems & structures which provide high levels cognitive & emotional processes along with other parts of the brain which are heavily interconnected.
3 Major systems make up the cerebral hemispheres:
- Limbic system- interconnected structures in the corebrain with major roles in emotion & memory. key structures include the hippocampus, amygdata, septum & cingulated gyrus
- Basil Ganglia- system of interlinked structures in the forebrain with important role of controlling movement. damage can cause movement disorders e.g parkinson's disease
more key termms
Amygdala- limbic system structure in the forebrain, important in emotional process
Parkinson's Disease- movement disorder characterised by tremor of hands & arms, this is a progressive disorder caused by damage to the basil ganglia
Motor Cortes- region of the cortex vital in controlling movement, damage can cause motor paralysis
Sensory Cortex- regions of the cortex where input from our sensory recptors is analysed. complex sensory systems such as vision & hearing have their own specialised cortical areas.
Cohen et al 1995
Aim- the role of general life stress on vulnerability to the common cold virus
Procedure- 394 p's completed a questionnaire on the number of stressful life events they had in the previous year, rated their degree of stress & their level of negative emotions e.g depression. The 3 scores were combined into what Cohen called 'stress index'. p's were exposed to the virus.
result-82% infected after 7 days number whose infection developed into clinical were recorded
Conclusion- The chance of developed cold (fail to fight virus) significantly correlated with stress index scores. life stress & negative emotions reduce the effectiveness of our immune system, leaving p's less able to fight viral infections.
study part 2
- indirect study (no direct measures to immune functions) but supported by Evans & Eclgington 1991 who found that the probability of developing a cold correlated with negative events in previous days.
- It did measure health outcomes (development of clinical colds), showing a relationship between life stress & illness, this can be compared with studies that use measures of immune function rather than illness outcome, there was no direct manipulation of the iv (stress index) so a cause & effect cant be confirmed
- study does not tell us which element of index is very important
study part 3
- clinical studies in psychology & medicine are always covered by rigorous ethical considerations, all applications are reviewed by professional committees which consider a variety of issues
- p's should be in good health with no illness prior study
- p's need to give fully informed consent & debrief after
- during study p's should be constantly monitored to check on reaction to viral challenge
- scientific value of study should be balanced against any psychological / physical distress to p
Kiecolt-Glaser et al 1984
Aim- naturalistic life stressors & their impact of measures of immune function
Procedure-75 med students who were preparing for final exams as an index of immune function, NK (natural killer) cell activity (part of immune system) were recorded from blood samples. 1 month before exam low stress and during high, questionnaires on negative life events & social isolation.
result- NK cell activity significantly reduced in high stress samples. greatest reductions were in students reporting social isolation
Conclusion- Examination stress reduces immune function, so people potentially more vulnerable to illness & infection, more noticeable effect on students with high levels of isolation
study 2 part 2
- in contrast to COHEN, this study did not asses actual illness outcomes although it did have direct measure of immune function
- although reductions in immune function should make people more vulnerable it might be that the significant reductions in the study are too small to increase the chance of stress-related illnesses.
- however KIECOLT-GLASER group have shown that small wounds take longer to heal with highly stressed groups e.g alzhemers p's
study 2 part 3
- usually measure NK cell activity as index to immune function, this is only component of a highly complex & sophisticated system. it was pointed out earlier that stress may alter the pattern of immune responses. e.g reduce natural immunity but leave specific immunity unchanged/ increased shifting balance from cellular to humoral immunity.
- in this study there was no manipulation of the IV (exam stress) and so a cause & effect cannot be confirmed, but the range of findings from a no. of different studies is highly suggestive of a relationship of life stress & reduced immune function
study 2 part 4
- usually measures of immune function in people experiencing natural life stressors e.g exams. they are not exposed to any further stressful procedures/ conditions apart from giving blood sample. p's would need to give fully informed consent & debrief after and be aware of mild stress of having immune functions measures
- studies where small wounds are inflicted & healing rates measures have SERIOUS ISSUES. degree of pain & distress. fully approval on ethical committee is required & fully informed consent & medical supervision
The overall conclusion of all these studies, using a variety of methods & p's is that life stresses such as examinations, negative life events, divorce etc can all reduce immune function & make people more vulnerable to illness & infection
The general adaptation syndrome
- a stressor is perceived & the HPA axis & the SAM pathway are activated
- levels of stress-related hormones surge
- heart rate & blood pressure increase & energy reserves are mobilised
- if the stressor persists the body's response systems maintain their activation, with levels of stress-related hormones & bodily arousal remaining high
- long periods of stress; chronic,eventually exhausts the body's defence system & its ability to maintain high levels of circulating stress hormones, this is the stage when stress-related illnesses may develop
The general adaptation syndrome - evaluation
- Sely's work has been extremely influential in developing the whole area of research into stress; he emphasised the central roles of the HPA axis & the SAM pathway & the links between chronic stress & illness.
- Selye emphasised that the GAS (general adaptation syndrome) was a common response to all stressors; i,e, he took response-based approach to stress, which as we have seen ignores all individual differences & the cognitive elements of perception & appraisal. Remember that much of Selye's early work was based on rats & a narrow range of physical stressors
- It is now though that stress-related illnesses are not caused by exhaustion of the body's physiological stress responses. Rather it is the effect of chronic/ long-lasting raised levels of stress hormones that can eventually lead to illness
Stress-related illnesses & the immune system
There is evidence that stress has an effect on the immune system.
What must be remembered is that :-
- stress is normal & expected part of life
- stress is an essential motivating & arousing factor energising us to work & achieve our goals
- the hormones released during bodily arousal associated with stress have a variety of effects on the body
- short term the body can cope long term leads to illness due to the effects of stress hormones
types OF stress
Segerstrom & Miller 2004 idenfitied
Acute time-limited stresses - usually studied under lab conditions & include experiences such as public speaking/ doing mental arithmetic. they usually last for between 5-10 minutes
Brief naturalistic stresses- everyday stressors of limited duration. the situation most often studied is that of students taking examinations
Chronic stress- long lasting stressors. they include caring for dementia patients, coping with long term illness, disability, long-term unemployment
stress & the immune system
There are many possible links between stress & physical illnesses e.g.
- increased heart rated & blood pressure can lead to physical damage to the lining of blood vessels / the muscles of the heart
- prolonged / chronic stress blood levels of glucose & free fatty acids can remain HIGH & contribute to the 'plaque' of arteries- this is called ATHEROCLEROSIS and can result in heart disease & strokes
- Other research has studied the effects of stress on the body's immune system & it is assumed that a weakened immune system leaves the body vulnerable to infection & illness
The immune system is a complex set of interacting processes that provides the body's defence against infection & illness.
stress & the immune system part 2 intro
We have learnt a great deal about the immune system from disorders of the system e.g immunodeficiency diseases such as AIDS which involved the destruction of the immune system & leaves people v.vulnerable
Then there are autoimmune diseases where the immune system fails to recognize host body tissues & attacks them in such conditions as cancer & diabetes
subdivisions of the immune system
Natural divisions- more primative system, made up of cells in bloodstream (white). these non-specifically attack & ingest (absorb) invading pathogens such as viruses & bacteria. these natural immunity cells include macrophages, phagocytes & natural killer cells
Specific Immuntiy- division of the body's immune system. Specific immunity is based on various types of lymphocytes that learn to recognise pathogens & destroy them
Cellular-division the body's immune system. cellular immunity involves a variety of lymphocytes that destroy intracellular pathogens such as viruses & bacteria (T lymphocytes- grow in the thymus gland)
Humral immunity- coordinated by another subset of lymphocytes called B cells (grow in bone marrow), as the grow & mature in the bone marrow. the end-product is secretion of antibodies from the B lymphocytes that attack & destroy extracellular (outside) pathogens such as bacteria & parasites
The components of the immune system do not function independently of each other. Lymphocytes release a variety of chemicals that can act as signals activating other parts of the system as a co-ordinated response to pathogens
meta-review of stress research
meta review (research tech in which results from all pepers studying a similar problem are statistically analysed together to provide more reliable overview)
The effects of stress are influenced by man factors, such as the type of stress, how long it lasts, & the individual's personality characteristics such as age, lifestyle & coping style, level of self-esteem, shame, emotions
Segerstram & Miller 2004
carried out study & drew the following 4 conclusions:
- acute time-limited stressors: overall these lead to an upregulation (increase/ improvement) of natural immunity, measured for instance as an increase of the no. of nk cells. this is logical as natural immunity is a fast response system that would be activated by the immediate onset of stressor
Segerstram & Miller 2004 meta-review of stress res
- brief naturalistic stressors: no overall effects on immune function, despite some significant findings e.g Kiecolt-Glaser et al 1984, but there was evidence for a shift from cellular immunity towards humoral immunity
- chronic stressors: chronic stressors have the most consistent effects on immune function. virtually all measures downregulation, these suppresive effects of chronic stress were consistent across gender & age groups
- non specific life events: S&M used life event questionnaire & found that the frequency & intensity of a range of life events showed NO significant changes in immune function. p's over 55 had a significant relationship between life even stress & reduction in immune system
general conclusions Segerstram & Miller 2004 meta-
- the clearest outcomes, short lasting stressors produce an increase in natural immunity and long lasting produce a downregulation in immune function -> global immunosupression
- S&M point out that acute time-limited stressors are the type which stimulates FIGHT OR FLIGHT stress response and GAS. rapidly occurring natural immunity responses are a natural adaptive response to these situation preparing the body to right infection
- Chronic long lasting stressors means that the immune system is basically stretched it goes beyond its ability to adapt & eventually leads to global immunosuppresion & stress related illness & infections
Global immunosuppression: downregulation (inhibition) of all components of the immune system, can be caused by chronic stress
- immune changes in response to stress are rarely simple,the involve shifts from the natural towards specific immunity & therefore a shift in balance between cellular & humoral activity
- there was no general evidence across all the studies for gender differences in immune reactivity to stress howeverKiecolt-Glaser did show differences in women's immune function comparison to men in the response to marital conflict
Further evaluative points
- how can you actually measure acute/ chronic stressors? because everyone is different in respect of e.g personality, past experiences, lifestyle
- what indicator of the immune function was measured? individual differences may not always be taken into account & generalisation made
chronic stress may lead to global immunosuppressio
How can chronic stress may lead to global immunosuppression
- hormones released as part of HPA activation directly affect the immune system
- there is clear evidence that high levels of corticosteriods in the bloodstream reduce the production of T lymphocytes and lead to shrinkage in the thymus glands
- the gland if a key component of the immune system
- (the effect of corticosteriods in suppressing immune functions has in fact led to them being used therapeutically!)
- autoimmmune diseases e.g cancer occur when specific immunity systems fail to recognise host tissue & attack
- steriod treatments suppresses immune function & can relieve the condition, a side effect if the patient if vulnerable to outside infections
Holmes & Rahe 1967 - the social redajustment ratin
aim- construct an instrument for measuring stress
procedure- examined the records of 5000 p's and made a list of 43 life events varying seriousness, which seemed to cluster in the months preceding the onset of their illness. they told 100 people that 'marriage' had been assigned an value of 500 & these judges were than asked to assign a number to each of the other life events in term of '... intensity & length of time necessary to accommodate...regardless of the desirability of the event relative to marriage'. So death of spouse was judged to require twice as much readjustment as marriage.the average of the numbers assigned to each event was then divided by 10, and the resulting values became the weighting of each life event. hence, the weighting for death of spouse was 1000, divided by 10 = 100. a sample of 43 life events is shown in later table.
the amount of life stress a person has experienced in a given period of time (say 1 year) is measured by the total number of life changing units (LCU's). these units are calculated by adding the mean values associate with the events the person has, the ranks simply denote the order.
Holmes & Rahe 1967 - the social redajustment ratin
when p's are given the SRRS, they are presented only with the list of life events & asked to tick the ones that apply.
1 Death of spouse 100
2 Divorce 73
3 Marital separation 65
4 Jail term 63
5 Death of close family member 53
6 personal injury/illness 53
7 Marriage 50 etc
Holmes & Rahe 1967 - the social redajustment ratin
results these can be expressed in terms of both the SRRS itself the relationship between stress & illness. whilst most life events were judged to be less stressful than getting married, 6 (including death of spouse, divorce) were rated as more stressful.
H&R also found evidence to support their belief concerning the relationship between stress & illness. High LCU scores for the preceding year were associated with the likelihood for experiencing some sort of physical illness with the following year.
conculsions- H&R concluded that stress could be measures objectively as an LCU score, that is, a number corresponding to the amount of change a person has had to face & adjust to during (usually) a year. This, in turn, predicts the person's chances of becoming ill following this period of stress, so that a score over 300 makes subsequent illness v.likely.
Holmes & Rahe 1967 - the social redajustment ratin
evaluation of srrs
- the srrs assumes that any change is by definition, stressful, regardless if positive/ negative. the available evidence seems to indicate that the undesirable aspects of events are at least important as the fact that they had change.
- some of the life events are ambiguous
- the list of life events is incomplete Lazaraus 1999
- life changes may only be stressful if they are unexpected and therefore uncontrollable
- most of the events are not everyday Kanner et al 1981 made a hassles scale. in a study of 100 men 7 women over a year he confirmed the prediction that hassles correlated with undesirable psychological symptoms, they also found that hassles were a more powerful predictor of symptoms than LCU
- Lazaraus 1999 LCU are distal causes of stress, we need to know the psychological meaning a person attaches to an environmental event, that is, its personal significance for the person concerned
holmes & rahe
study carried out in U.S so the events & how they were rated would have been culturally specific & no objective assessment of the degree of adjustment, relied on opinion
as a questionnaire with no manipulation of variables there are no serious issues with this type of study. standard procedures of informed consent & debriefing would be followed
rahe et al 1970
Rahe et al 1970
aim: link between LCU & illness (in sample of healthy p's)
procedure: 2500 male us navy personel filled in the SRRS for the previous 6 months they were than followed up over 7 months tour of duty & all stress related illnesses recorded & rated for number & severity = overall illness score
result: positive correlation of 0.118 between LCU scores & illness scores, although this is relatively low correlation it was statistically significant
conclusion: there is a relationship between life events & the development of stress-related illness, as the correlation was relatively low, however, other factors may also be involved
rahe et al 1970
- used male us navy personnal & results are therefore gender & culturally specific & should be generalised to other groups with caution
- retrospective questionnaires can be problematic
- all illness outcomes were recorded, no specific hypothesis, about which illness could be stress related to LCU
- correlational study, do not imply causality only an association, they are particularly impatent when for practical & ethical reasons the investigator cannot manipulate the IV
- informed consent & debried
- some distress in recalling traumatic life events
holmes & rahe - evaluative commentary
these studies especially the American sailor study does support other studies using SRRS, which shown similar correlation & this is despite it being culturally specific.
no account is taken of the emotional impact of an event, either positive/ negative.
the scale takes no account of individual differences, each of us could have a different outlook on a specific life event
retrospective self report over the preceding year can be unreliable often reveals variability in accounts for the same thing
results are usually in the form of correlation which do not indicate cause &effect between 2 variables - they only show that there might be a relationship between them
Stress in everyday life
Everyday stress are all considered to be part of everyday life.
A major life event however is completely different & will to a greater / lesser extent be dependent upon the severity of the event & the effect it has on the individual & their approach to the event.
So that stress that is seen as part of everyday life can be relatively minor/ short lasting or serve & possibly long lasting
Each & everyone of us can be stressed at sometime but not necceserly develop stress related illness - stress is an unavoidable factor of life, both at work, exams or home,and of course stress exists when perceived demands outstrip perceived resources (transactional model)
there are many ways of measuring the degrees of stress in someone's life.
there are difficulties with questionnaires in that there is possible exaggeration & lying as it is social sensitive data which could lead to social desirability. also qualitative data could lead to issues with analysis which could mean misinterpretation from research also the question asked may be misinterpreted by the p;s. also if sampling is not accurate could lead to a biased sample
style of questionnaires
there are different styles of questionnaires
- self-report questionnaires on frequency of life stress
- self-report questionnaires on perceived/ subjective stress
- semi-structured interviews , in which the p's talk through their life stressors & the trained interviewerasses the impact of these stressors
retrospective: refers to the past,p's may asked to recall events from the previous years
prospective: refers to future, involve following p's over a period of time from start of the study
other life event scales
- LES; Sarason et al. 1978 allows people to rate 57 life events in terms of severity of impact & whether impact if positive/ negative. this allows for individual differences. specialised sections can be added for particular groups such as students. the life events scale produces 3 scores- neg change, pos change total change (similar to srrs) in general neg life changes scores correlate more highly with illness outcome
- Hassles scale; Lazaruas ; Kanner et al 1981 reg sources of stress in people lives from day-to-day. the original scale had 117 items covering all aspects of daily life. L felt that life also contained positive events (uplifts) that could counteract the neg. an uplift scale of 135 items was made
- ADE Daily experience scale; Stone & Neale 1984similar but better
personality factors- type a behaviour
Type A behaviour (tab) refers to a pattern of behaviours & attitudes that has long been linked to a vulnerability of stress-related illnesses.
The type a concept evolved from the work of Friedman & Rosenman in the 1950's/60's.they studied the characteristics of patients with coronary heart disease (chd) & decided that a particular pattern of behaviour seemed to be associated with a vulnerability to heart disease. the characteristics are listed below, they also defined type B pattern that was essentially opposite to A, not competitive
Time pressured- e.g unhappy doing nothing, always working to deadlines, multi-tasking
Competitive- e.g always oriented towards achievements, plays to win at work/sport
Hostility- e.g easily irritated & impatient with co-workers, easily angered, anger can be direct inwards
personality factors- type a behaviour - study
Rosenman et al 1976
Aim: to investigate whether type A is more likely to develop CHD
procedure: studied 2454 mid aged men on the west coast of U.S, they were categorised as either type a/b by structured interviews. as the p's answers the questions the trained interviewer also notes behavioural signs of the type a pattern. these could be rapid finger tapping on the table, restlessness, pace of speech. answers to the q's & the general behaviour are put together to provide overall assessment of tab
result: the p's were followed up for 8.5 years, during this time 257 heart attacks, 69% of which were type a. this was a significant effect even when lifestyle risk factors were controlled
conclusion: high tab individual was vulnerable to heart disease
personality factors- type a behaviour - study
- study is culturally & gender specific, so findings can be generalised with caution
- many individ & lifestyle variables that can affect vulnerability although some controlled may of missed some
- high ecological validity
- p's were volunteers gave informed consent & debriefed at end
- no manipulation so no chance of psychological harm
personality factors- hardiness
The concept was introduced by Kobasa 979 who was interested in factors that might protect people against the effects of stress. there are 3 elements:
- control- this is the idea that you can influence events in your life, including stressors
- commitment- this is the individual's sense of involvement & purpose in life
- challange- this refers to the idea that changes in life should be viewed as an opportunity rather than a source of stress
Kobasa devised questionnaires to asses control, commitment & challenge, & in herecilly studies found that people with high scores on these dimensions reported fewer stress-related symptoms, this work only male white-collar workers & could lack eco validity. But findings were supported by later studies Kobasa 1982 & Beaseley et al 2003 who investigated stress in uni students, students who scored more highly on hardiness showed reduced levels of psychological distress.
personality factors- hardiness & type a
Although the area of research into personality & stress has no. of controversies & disagreements there are some obvious connections between tab & concept of hardiness. according to Kobasa, high levels of 3 elements protect against the harmful affects of stress. research into tab suggests that type a people are less vulnerable to effects of stress than was originally thought.
They look back at the characteristics of people who score highly on tab you will see that they have high levels of competitiveness & are very achievement orientated.you could argue that people with these characteristics are showing commitment & also see life as a series of challenges to overcome. Commitment & challenge are key components of hardiness, so a conclusion might be that type A behaviour pattern also contains aspects of hardiness
- some characteristics of TAB such as time pressure may increase vulnerability
- other such as commitment increase resistance
- so the TAB pattern is made of factors some increase/decrease risk
- the mixed pattern explains why type a study with heart diseases are inconsistent
other personality types
There has been various attempts to identify other personality types vulnerable to illnesses, some of which could be linked to stress. Eysenck 1988, proposed 2 types of personality: the 1st was a personality type vulnerable to cancer & this was associated with difficulties in expressing emotions & social relationships. the 2nd was a vulnerable to CHD, this was similar to TAB, high levels of anger & hosility.
However as with the work on TAB,there is no consistent evidence linking these personality types wit either cancer or conronary heart disease
More recently Denollet 200 has proposed yet another personality type that in his view is vulnerable to heart disease. this is the type D personality (distresses) people with this experience high levels of neg emotions (similar to hostility on TAB) & school inhibition. ie. they tend to avoid social interaction. Denollet and his group have shown a no. of studies (Denollet et al 1996; Denollet & Van Heck 2001) that with high levels of neg emotions combined with social inhibition associated with risk of heart disease.
As we can see thee has been numerous attempts to link aspects of personality to stress-related illnesses. these approaches assume that personality is a factor influencing the relationship between stress & its effects on the individual. However we have also seen that such relationships are difficult to demonstrate consistently. Looking at the working on TAB, hardiness & other personality types, what we can conclude is that neg emotions seems to increase stress-related vulnerability to heart disease
We should also note at this stage that in any study there are always factors that could influence the results. e.g high levels of anger may be associated with smoking / drinking & other dysfunctional lifestyles. they may also lead to social isolation, which Denollet work suggests it is another important factor in stress/ illness relationship.