PSYA2 Biological Psychology (stress)

Sympathomedullary Pathway

The hypothalamus triggers activity in the sympathetic branch of the autonomic nervous system- which is a branch of the peripheral nervous system.

The sympthetic branch becomes more active when the body is stressed and using energy.

It stimulates the adrenal medulla within the adrenal gland which release adrenaline and noradrenaline into the bloodstream.

These affect the body in several ways: Blood pressure and heart rate increase to get blood quicky to areas of the body where its needed for activity.

The result of these changes in the body is ready to use energy.

Pituitary Adrenal system

If the stress is long term, say several hours or more, then the sympthomedullary response will start ti use up the body's resources. So, a second system produces a countershock response which supplies the body with more fuel.

The hypothalamus also triggers the release of CRH.

CRH stimulates the anterior pituitary gland.

Thuis then releases a hormone called ACTH.

ACTH travels through the body and then stimulates the adrenal cortex near the kidneys.

the adrenal cortex then releases corticosteroids which give us energy by converting fat and protein.

This energy is needed to replace that used up by the initial reaction to stress, e.g. running away.

Method: Monkeys were put in pairs and given electric shocks every 20 seconds for 6 hours. One monkey of each pair ('the executive') could push a lever to postpone eachshock. The other could not delay them.

Results:The 'executive' monkey were more likely to develop illness (ulcers) and later die.

Conclusions: The illness and death was not due to the shocks but to the stress that the executives felt in trying to avoid them. In the long term, this stress reduced te immune system's ability to fight illness.

Evaluation: The experiment has ethical issues- the experiment was very cruel and would not be allowed today. Also we can't generalise results from monkeys to humans.Furthermore we know that people with little control over their own lives (such as those with low level jobs and the long-term unemployment), can experience high levels of stress, which this research cannot explain.

Method: In a study with an independant measures design, a punch biopsy was used to create a small wound on the arms of 13 women who cared for relatives with Alzheimers disease (a very stressful responsibility). A control group of 13 people also took part.

Results: Wound healing took an average of 9 days longer for the carers than those in the control group.

Conclusion: Long-term stress impaires the effectiveness of the immune system to heal wounds.

Evaluation: Sweeny (1995) also found that people caring for relatives with dementia took longer than a control group to heal their wounds. However, for both studies the two groups may have varied in othe ways apart from the stress of being a carer. The effects on the carers could be due to lack of sleep, poor diet etc, and not just the stress they experienced. The study only contained a small amount of participants- for more reliable results it should be repeated with a larger number.

Method: In a laboratory experiment, 39 participants did one of these stress inducing tasks (a maths test, a stroop test and public speaking). Their blood pressure and the extent to which the vessels around their heart contracted (low,medium or high myocardial ischaemia) was measured. Partcipants were instructed not to take any prescribed heart medication prior to the study.

Results: Participants with the greatest myocardial ischaemia showed the highest increases in blood pressure. A small number participants who showed mild or no myocardial ischaemia only had very moderate increase in blood pressure.

Conclusion: Stress may have a direct influence on aspects of body functioning, making cardiovascular disorders more likely.

Evaluation: Although the effects were clearly linked to stress, it can't be said that one causes the other. Also it wasn't shown whether the effects also occur at other times. They might sometimes happen even if the person feels relaxed- and therefore couldn't just be linked to feeling stressed. Not everybody showed the same reactions, which suggests individual differences between the participants may also have played a role. The ecological validity of the study was reduced because it took place under laboratory conditions that weren't fully representative of real-life stress. However, the findings of the study are supported by Williams (2000)- it was seen that people who got angry easily or reacted more angrily to situations had a higher risk of cardiovascular problems.

Life Changes-these are major events that require a significant change in a person's life style. These events and the adjustment they cause us to make can be major sources o stress.

Holmes and Rahe (1970)- LCU and illness

Aims:to test the hypothesis that the number of life events a person experiences would be positve correlated with illness.

Method:In a correlational study, more than 2500 American Nave seamen were given a form of the SRRS to complete just before they set sail on military duty. They had to indicate all of the events they had experienced over the previous six months.

Results:Higher LCU scores were found to be linked to a higher incidence of illness over the next seven months. Positive correlation--> stress- life changes

Conclusion:the stress involved in the changes that life events bring is linked to an increased risk of illness.

Evaluation:The results are not representative of the population and can only be generalised American Navy seamen. Also, the results don't explain the individual differences in response to stress. There are also limitations associated with using correlational research. Tou can't assume a causal relationship between the variables- the correlation might be caused by a third unknown variable. As well as this, there are problems with using the SRRS to rank stressful events. The questionnaire might not have been the most reliable method to investigate this problem. Because of social desirability they m ay have lied to be percieved in the best possible light. So therefore the results may not be valid due to social desirability.

Daily Hassels: Day to day events that cause you stress.

The accumulation effect: This is when all the daily hassels that you have mount up and become too much- measured through depression and anxiety.

The amplification effect: This is when a situation is made bigger than it already is because your resources are being depleted.

Definition: Aspects within the work environment that we experience as stressful therefore causing a physiological changes to our body.

Factors in the workplace that act as stressors

Lack of control- We may not have much influence over the type and amount of work we do or, where and when we do it.

Work Pressures- Having too much work to dom, maybe with strict deadlines.

Marmot et al (1997)- Lack of control and illness in the workplace.

Method: Over 7000 civil service employees working in London were surveyed. Information was obtained about their grade of employment, how much support they felt they had etc.

Results:When the medical histories of these employees were followed up 5 years later, those on lower employment grades who felt less control over their work (and less social support) were found to be more likely to have cardiovascular disorders.Participants on the lowest grade of employment were four times likely to die of a heart attack than those on the highest grade.

Conclusion:Believing you have little control your work influences work stress and the development of illness.

Evaluation: The study only looked at 'white collar' work (office type jobs), so the results may not apply to other jobs. Smoking was to be more common in those who developed illness. So, perhaps those who felt less control at work were more likely to smoke- and the smoking caused heart problems rather than the stress. Other factors (e.g. dietand exercise) may be linked to job grade and could be causing ilness rather tha the percieved lack of control. The research is correlational, so it isn't possible to establish a cause and effect relationship between lack of control and illness. Data was obtained using questionnaires. This may have encouraged Participants to be 'truthful' than they would have been if interviewed.

Method:Approximately 3000, 39-59 year old American males were assessed for their personality characteristics, using interviews and observations. At the start of the study none of them had CHD (coronary heart disease).

Results:Eight years late 257 of them had developed CHD. 70% of these were classed as 'type A' personality. This includes being a 'workaholic', extremely competitive, hostile to others and always in a rush. The other participants were classed as 'non type A' and were less competitive and impatient. These results were found even when extraneous variables of weight and smoking were taken into account.

Conclusion:Type A personalities seem to be at a higher risk of stress-related illnesses, such as CHD.

Evauation:The study doesn't prove that personality characteristics can cause stress and illness. It could be the other way round. For example, Type A personality may develop as a response to being under stress (from work etc.). Only males used- can't generalise to population. Social desirability- not being honest in the interviews.

There are three main characteristics of hardy personalities:

Control: They are in control over their lives and they don't let anything outside their lives take over. This is known as having an internal locus of control.

Commitment:They are involved with the world around them and have a strong sense of purpose. This means that they have made certain goals or aims that they want to achieve and nothing will stop them reaching that goal.

Challenge:They see life challenges as problems to be overcome rather than as threats or stressors. They enjoy change as an opportunity for development. They are not afraid to try new things and see it as a positive thing.

Kobasa (1979)- Hardy personality encourages resilience.

Studied stress levels of 800 American business executives.

150 were classified as high stress.

Of the 150, some had low illness record where as others had a high record.

Suggest that something else was modifying the effects of stress because individuals with the same stress levels had different illness records.

The individuals in the high stress/low illness group second on all 3 characteristics of the hardy personality.

Evaluation: Point: Critics argue that the negative affectivity concept could be used to explain characteristics of the hardy personality.

Evidence: Watson and Clarke (1984) found that high NA individuals are more likely to report distress and dissatisfaction, dwell more on their failures and focus on negative aspects of themselves and their word.

Comment: There is a correlation between the NA individual and the hardy personalities which shows people with the hardy personality may just have low negative activity and not necessarily and overall hardy personality.

Point: Most of the research support for a link between hardiness and health has relied on self report questionnaires.

Evidence: The study shows the internal reliability for the challenge component of hardiness.

Comment: This shows that the study on hardiness can not be fully reliable so results cannot be generalised.

Problem- focused techniques: These techniques involve making a plan about how to cope with a stressful exerience and then following the plan. For example, a person who feels stressed at work could decide to apply for new jobs until they get a new, less stressfgul job.

Emotion- focused techniques: These techniques involve adapting both behaviours and cognitive processing to reduce stress. For example if you're facing a week of exams, you might decide to go out and watch a film to prevent yourself from having to think about all the work. However the problem with this type of technique is that the stressor still remains and it isn't an effective way of dealing with the situation in the long term. Specific methods such as SIT and hardiness training focus on adapting the cognitive processing.