- Created by: Emily
- Created on: 31-05-13 10:44
Sympathomedullary Pathway, Fight or Flight, Acute
Acute stressors activate the sympathetic branch of the ANS. The SNS prepares the body for fight or flight. This is achieved by the release of noradrenaline which activates internal body organs associated with fight or flight. SNS changes include an increase in heart rate and blood pressure, increase in pupil size.
Neurons of the SNS travel to the adrenal medulla, causing it to release adrenaline. Adrenaline boosts the supply of oxygen & glucose to the brain and suppresses non-emergency bodily processed, such as digestion.
Once the stressor has passed, the heart beat slows down again and reduce blood pressure, restoring the body to its normal resting state.
Chronic Stress, Long-Term Stress
This response is activated under ongoing stressors. A message is sent to the hypothalamus and activation of this area leads to the production of CRF, which is released into the blood stream.
CRF causes the pituitary gland to release ACTH. This is then transported to the adrenal glands, specifically the adrenal cortex.
Once activated, the adrenal cortex releases cortisol. Cortisol can lower sensitivity to pain, however it can also lower the immune system response. Prolonged release of ACTH causes the adrenal cortex to increase in size to produce more cortisol.
Stress can lead to cardiovascular disorders. Stress causes an increase in heart rate and this may lead to wearing away of the lining of blood vessels which can cause atherosclersosis and therefore a heart attack.
Some people respond to stress with greater feelings of anger (acute stressors) - Williams asked 13,000 people to complete an anger questionnaire. 6 years later their health was checked. Those highest on the anger scale were far more likely to have had a heart attack.
Russek looked at heart disease in medical professionals (chronis stressor). One group of doctors was designated high-stress (GPs & Anaeshetists), while others were classed as low-stress (pathologists & dermatologists). Russek found that heart disease was greatest among GPs and lowest among dermatologists. This supports the view that stress is linked to heart disease.
Stress-Related Illness & The Immune System
Key Study - Keicolt-Glaser
- Natural experiment with 75 medical students
- The researchers assessed immune system functioning one month before an exam & then during the exam period itself.
- Keicolt-Glaser found that immune system functioning was significantly reduced from a blood sample taken during the exam period compared to one taken a month before. This suggests that short-term stressors reduce the efficiency of immune system functioning.
Evaluation of Keicolt-Glaser study
- Natural experiment - high ecological validity however, there could be problems with confounding variables.
- Sample size - 75 is a very small sample & they only used medical students and therefore we cannot generalise the results to other students.
- Short-term stressors have been found to increase levels of slgA, which helps protect against infection.
Stress & Psychiatric Disorders
Stress & Depression
Brown & Harris found that women who suffered chronic stress conditions e.g. having more than 3 children under the age of 14 and being unemployed, were more likely to develop depression.
They also reported that working-class women were more prone to depression than middle-class women because of the stress of having to leave home for work and having to leave their children in the care of others.
Life Changes as Stressors
Key Study - Holmes & Rahe
- 2,500 male American sailors were given SRRS to assess how many life events they had experiences in the last 6 months.
- Then over the following 6 months on duty, detailed records were kept of each sailors health.
- They found a possitive correlation - as life change units increases, so did the frequency of illnesses.
Evaluation of Holmes & Rahe study
- There are concerns over the validity of the study because we cannot be certain about the accuracy of people's memories for life events.
- The study only used males and therefore we cannot generalise the data to women.
- The participants were also all American and therefore we cannot generalise the results to other countries.
- Correlation doesn't mean that life changes caused illness.
Evaluation of Life Changes as Stressors
- Most studies have only found correlational data, failing to demonstrate a causal relationship between life events & stress-related illness.
- There are huge individual differences in the impact of life events such as pregnanycy, retirement, Christmas etc. Because the imparct of these event varies from person to person it becomes hard to predict illnesss from SRRS scores alone.
- Major life changes are relatively rare in most people's lives, so relatively minor daily hassles are more likely to be a significant source of stress. A researcher found a significant relationship between health & daily hassles by not for health & life events.
- Research using the SRRS appears to indicate that any life-changing event has the potential to damage health because it requires significant readjustment. Some critics argue that only undesired, unscheduled and uncontrolled changes tend to be really harmful.
Daily Hassles as Stressors & Daily Uplifts
Key Study - Bouteyre et al
- Investigated the relationship between daily hassles & mental health of students during the initial transition from school to university. The students completed a hassles questionnaire & a depression questionnaire.
- They found that over 40% of the new students suffered from depressive symptoms & there was a positive correlation between scores of the hassles scale and the incidence of depressive symptoms.
Gervais asked nurses to keep diaries for a month, recording all the daily hassles & uplifts while at work. After a month, it was clear that daily hassles increased job strain and decreased their job performance. However, daily uplifts appeared to counteract the stressful impact of these hassles as well as improving job performance.
Evaluation of Daily Hassles as Stressors
- Most research on daily hassles has asked participants to assess the impact of hassles experiences over the previous month. The accuracy of such memories tends to vary accordingly to the time interval involved. More recently, researchers have started to use the diary method where stressors & feelings are recorded daily.
- Even when memories are reliable, the data they produce are only correlational. This means we cannot draw causal relationships between daily hassles & our health.
- Research in this area gives us an insight into understanding road rage. A psychologist found that participants who reported a difficult day at work tended to report higher levels of stress on their drive home.
- Miller et al found gender difference in the impact of pets on an individual's life. For females, pets were more commonly associated with uplifts (e.g. leisure), but for males they were more likely to be associated with hassles (e.g. cost of upkeep).
Key Study - Johansson et al
- 14 saw mill finishers from Sweden were compared to 10 cleaners
- Their levels of stress related hormones in their urine was measured on both work days & rest days
- Records were kept of stress-related illnesses
- Results showed the the 14 finishers secreted more stress hormones on workdays than on rest days compared to the 10 cleaners. Thye also showed higherlevels of stress related illness
Evaluation of Johansson's study
- No ethical issues - the workers were going about their usual jobs and they were not exposed to any psychological harm or distress through the process.
- It's reductionist - it claims that work is the only cause of stress
- Ethnocentric - only Swedish people were used and therefore we cannot generalise the results to other countries.
- Small sample size
Type A & Type B Personalities
Friedman & Roseman described the Type A personality as possesing 3 major characteristics:
- Competitiveness & achievement striving
- Impatient & time urgnecy
- Hostility & aggressiveness
These characteristics are believed to lead to raised blody pressure & an increase in levels of stress hormones, both which are linked to ill health.
Type B behaviours, by contrast (relaxed & easy going), decrease the risk of stress-related illness.
Type A & Type B Personality Study
Key Study - Friedman & Rosenman
- Using structured interviews, 3,200 Californian men aged 39 to 59 were categorised either Type A or Type B.
- Eight years later, twice as many (12%) of those who had type A personalities had died of CV problems than those who were classified as Type B. The Type A men also had higher blood pressure and higher levels of cholestrol.
Evaluation of Friedman & Rosenman's study
- Correlational study - cannot establish cause & effect
- Interview - people lie and also investigator effects could occur
- Other research has found different results - research has found no relationship between Type A personality & death from CHD.
- The sample only used Californian men who were aged between 39 and 59 we therefore we cannot generalise - lacks external validity
Personality Factors, The Hardy Personality
Kobassa claims that some people are more resistant to the harmful effects of stress because they have a 'hardy personality' which consists of:
- Control - Hardy people see themselves as being in control of their lives rather than being controlled by external factors
- Commitment - Hardy people are involved with the world around them and have a strong sense of purpose
- Challenge - Life challenges are seen as problems to overcome rather than stressors
Hardy Personality Study
Key Study - Kobassa
- The stress scores of 800 American business executives were determined using Holmes & Rahe's SRRS & hardiness was assessed using a hardiness test
- Kobassa found that 150 of the participants were classified as having high stress levels. However, these individuals differed in their illness record over the same period. Those with low levels of illness were more likely to have scored high on all 3 characteristics of the hardy personality and vice versa
- Hardy people are simply low on 'negative affectivity' (NA) - they don't dwell on their failures or negative aspects of themselves
- Much of the data collected has been obtained through self-report questionnaires - tend to be long and awkward wording and negatively worded items
- The concept of hardiness has been used to explain why some soldiers remain healthy even under extreme stress
Stress Innoculation Training (SIT)
Meichenbaum believed that although we can't change the causes of stress, we can change the way we think about stressors and the way we react to them. People can be trained to 'innoculate' themselves against a stressor before it arrives.
The 3 mains phases of SIT are:
- Conceptualisation - clients are taught to think differently about stressors i.e. problems that can be solved
- Skills Aquistition - coping skills are taught and rehearsed
- Application - the learned coping skills are applied in increasingly stressful situations
Evaluation of SIT
- Meichenbaum compared SIT with systematic desensitisation to deal with snake phobias - Both were effective but SIT helped to reduce fear
- Psychologists found the sessions of SIT reduced anxiety & stress among students over time, as well as improving academic performance
- SIT gives the client necessary skills so they are less affected by stressors in the future
- SIT is time consuming & requires high motivation. However Meichenbaum has demonsrated the effectiveness of relatively brief periods of training
- SIT is unnecessarily complex - it is possible that effectivness of SIT can still be achieved with just some of its elements
Kobassa identified a personality type that was especially resistant to stress - the hardy personality. Kobassa believed that people could be trained in hardiness, to help them manage stress better.
Hardiness training involves:
- Focusing - the client is taught to recognise the sources of stress & the psychological signs of stress
- Reliving stress encounters - the client is given an insight into current coping strategies by relieving previous encounters & their response to them
- Self-Improvement - These insights can be used to move forward & learn new techniques. For examples seeing stressors as challenges they can take control over rather than problems they must give in to
Evaluation of Hardiness Training
- Hardiness training has been shown to be effective in many different populations
- Hardiness training has been used to increase commitment to training in Olympic swimmers, by helping to control aspects of their daily lives that might interfere with their training schedules
- Training must first address basic aspects of personality & learned habits of coping that are difficult to modify, therefore hardiness training cannot be seen as a rapid solution to stress managment
- Used to treat anxiety that is a consequence of stress, they do this by slowing down the activity of the central nervous system
- GABA (Gamma-Amino-Butyric-Acid) is a neurotransmitter that is the body's natural form of anxiety relief - GABA makes it harder for neurons to be stimulated, making the person feel more relaxed. BZs enhance the action of GABA, making neurons in the brain even more resistant to excitation & making the person feel a lot calmer.
- Reduce activity of adrenaline & noradrenaline which are part of the sympathomedullary pathway. They bind to receptors on the cells of the heart & other parts of the body that are stimulated during arousal
- By blocking these receptors, it is harder to stimulate these cells, so the heart beat slower with less force & blood pressure falls. The person then feels calmer & less anxious
Evaluation of Drug Therapies
- Research support - Kahn et al found that BZs were significantly superior at reducing anxiety compared to a placebo
- Drugs have been shown to be effective in managing the effects of stress. A meta-analysis found that BZs were more effective than other drugs in reducing anxiety
- Drug treatments require little effort from the patient
- Patients exhibit withdrawal symptoms when they stop taking BZs, indicating psychological dependence
- Side effects - for BZs, these include increased aggression and impairment of memory. Some studies have linked BBs to an increased risk of developing diabetes
- Effectiveness of drug treatments only lasts as long as the person takes the drugs - drugs treat the symptoms not the cause