The Activation of the Sympathomedullary Pathway
1) Stressor triggers hypothalamus which triggers activity in the sympathetic branch (of the autonomic nervous system.) The sympathetic branch then stimulates the adrenal medulla (within the adrenal glands), which releases adrenaline and noradrenaline into the bloodstream.
2) These affect the body by:
- Blood pressure and heart rate increase
- Digestion decreases
- Muscles tense
- Perspiration increases
- Breathing rate increases
3) Body is then ready for Flight or Fight!
The Activation of the Pituitary-Adrenal System
Eventually, the sympathetic response will use all the body's resources, so for long-term stress a second system is needed to provide the body with more fuel.
1) Hypothalamus triggers the release of CRH which then stimulates the anterior pituitary gland which then releases a hormone called ACTH.
2) ACTH travels through the body and stimulates the adrenal cortex (near the kidneys.)
3) Adrenal cortex releases corticosteroids which give us energy by converting fat and protein.
Hans Selye - Stress is a Three-Stage Response
- Rats given harmless injections developed stomach ulcers - Hans concluded that the stress of the daily injections made them ill.
General Adaption Syndrome (GAS):
1) The Alarm Stage - Making the neccessary physical response to be prepared for 'Flight or Fight'.
2) The Resistance Stage - If the stressor is long-term, our body's adapt to the situation and we seem to copy normally.
3) The Exhaustion Stage - After long term exposure our bodies will be unable to cope, alarm signs may return and we may develop illnesses.
Studies on Stress and Illness
Krantz et al.
- Long-term Stress can affect the Cardiovascular System.
- Lab. ex., 39 pp's did 1/3 stress-inducing tasks.
- Blood pressure and heart contractions was measured.
- High contractions correlated with high blood pressure and vice versa.
- Ev: correlation not cause, lab ex - lack ec. valid., indvidual differences, supported by Williams (2000) - people who got angry easily were at higher risk of CVD.
Brady et al.
- Stress can affect the Immune System.
- Monkeys, put in pairs, shocked every 20 seconds for 6 hour sessions. One monkey could delay the shocks (executive), the other could not.
- The executive was more likely to develop ulcers and die.
- ethics, cant generalise to humans, people with low level jobs experience high level stress which this research cant explain.
Life Changes are a Source of Stress
Holmes and Raye
Social Readjustment Rating Scale (SRRS). Ranked events from most stressful to least stressful with each having a score of Life Change Units (LCU). Possitive correlation between score on SRRS scale and likelihood of illness.
Rahe et al.
- Correlational study, 2500 Navy seamen, given SRRS before military duty, indicated events experienced in the previous 6 months.
- Higher LCU scores linked to higher illness over the next 7 months.
- Not representative of population - only generalised to navy seamen, correlation not cause, issues with SRRS. (doesn't seperate positive and negative events, long term minor source stressors eg. work stress isn't considered.)
Daily Hassles Stress
Kanner et al.
- 100 adults completed questionnaire each month for 9 months choosing which hassles they had experienced in that month from a list of 117, and rating them on how severe it had been for them.
- Those with high scores were more likely to have physical and psychological health problems.
- Conclusion: daily hassles are linked to stress and health
- Correlation not cause,quantitative data - potential useful data is missed, rely on pp's recall to be accurate, pp's may not be truthful.
Workplace Stress comes from 5 different areas:
Relationships at work, Work pressures, The physical environment (can be noisy, overcrowded, too hot or cold), Stresses linked to our role (worrying about job security, prospects for promotion), Lack of Control.
Marmot et al.
- 7000 civil service employees working in London were surveyed.
- Info was collected on grade of employment, how much control they thought they had, how much support they had, etc.
- Medical histories were looked up 5 years later, those with lower control and lower employment grade were more likely to have CVD. They were also 4 times more likely to die of a heart attack.
- Con: believing you have little control over your work influences stress and illness.
- Eval: Only looked at white-collar jobs, extraneous variables (smoking, diet), correlation not cause, questionnaires - people may not be truthful.
Personality Type and Stress - Individual Differenc
Type A - Competitive and ambitious
Type B - Non-competitive, relaxed and easy-going
Friedman and Rosenman
- 3000 39-59 y/o American males were assessed for personality type using interviews and observation.
- 8 years later, 257 of them developed CHD, 70% of these being classed as Type A.
- Eval: having 2 personality types is too simplistic, correlation not cause, limited sample - cant generalise, pp's may not have been honest - Social Desirability Bias.
Hardiness and Stress - Individual Differences
Hardy - Committed (involved in what they do), Challenge (enjoy and see as an opportunity), Control (strong feeling of it over their life and what happens to them - internal locus of control).
Non-Hardy - views life experiences negatively, unable to cope with situations, external locus of control, give up easily.
Evaluation: Difficult to measure hardiness, Cannot establish cause and effect
Physiological Stress Management
Drug Treatments work in two ways...
Slow down the activity of the central nervous system - anti-anxiety drugs BZs.
Reduce the activity of the sympathetic nervous system - Beta blockers.
Biofeedback gives people information about their bodily processes...
1) Persons monitored and given feedback on heart rate, blood pressure and muscle tension.
2) They are taught how to conrol these symptoms through techniques such as muscle relaxation, mediation or breathing control exercises.
Strengths and Weaknesses of Physiological Stress M
+ Drugs and Biofeedback are effective: Drugs are quick and effective in reducing symptoms. Biofeedback helps teenagers gain control over their symptoms.
- Both treat symptoms not underlying cause.
- Drugs have side effect: dizziness, tiredness, withdrawal symptoms.
+ No side effects of Biofeedback.
+ Drugs are easier to use then biofeedback: Drugs are easy to perscribe and use, Biofeedback needs specialist equipment and expert supervision - costly and time consuming.
Psychological Stress Management
Coping can be Problem-focused (making a plan, following it) or Emotion-focused (adapting behaviour and thought to reduce stress).
Meichenbaum's Stress Inoculation Training (SIT)
- Conceptualisation (identify fears and concerns with therapist.) Skill acquisation and rehearsal (train to develop skills like positive thinking and relaxation.) Application and follow-through (Practise new skills in real-life situations.)
- Focusing (recognise symptoms of stress), Reliving stressful encounters (analyse situations to learn to cope better), Self-improvement (take on challenges that build confidence to give you a sense of control).
Psychological Stress Management continued...
Cognitive Behavioural therapy (CBT) aims to alter thought processes.
Rational-Emotive Therapy (RET) - Ellis suggested the ABC Model
- (A) Activating Event which leads to a (B) Belief about why it happened which leads to a (C) Consequence.
- RET focuses on encouraging people to change irrational beliefs into rational beliefs for a more positive consequence.
Weaknesses of Psychological Methods:
- Only suit a narrow band of individuals (determined), Research based on white, middle-class folk so cant generalise, procedures require commitment, time and effort, Concepts may be too complex.