Stress

• The general adaptation syndrome (GAS) was developed by Selye (1936), and it refers to the way in which the body reacts and adapts to stress both on a short- and long-term basis.
• Selye's GAS model has 3 stages. Alarm reaction (sympathetic nervous system activated, ForF). Resistance (if stressor continues, adrenal cortex releases cortisol). Exhaustion (body's resources of energy depleted, can lead to immunosuppression)
• Selye studied rates to asses the long and short term effects of stress. He exposed them to a variety of stressors. The results were the rats got sick with a enlarged adrenal cortex and stomach ulcers.
• Leshem supports Selye when they replicated the study on plants. It resulted in decrease of growth. Even though it is plants, it supports Selye's theory that there was a universal biological underpinning to the stress response.
• A limitation to Selye's rats is that it was an animal study. For example humans have ways of coping with stress and social support unlike rats.
• The sympathomedullary is a stress response concerned with short-term (acute) stressors. The key system involved in the pathway is the sympathetic adrenal medullary system (SAM) better known as the “fight-or-flight” response
• The SAM pathway goes: Hypothalamus, sympathetic NS, adrenal medulla, adrenaline or noradrenaline released.
• Taylor et al criticised the SAM model due to it's gender bias. They foudn that women are more likely to tend and befriend.
• a further criticism of research conducted into the sympathomedullary pathway is that it uses findings from animal studies. McCarty found that rats of different ages had different responses to sympathetic stimulation.
• The hypothalamic-pituitary-adrenal system (HPA) is activated during times of long-term (chronic) stress. It goes: Hypothalamus releases CRH, pituitary release ACTH, ACTH travels through the blood stream and stimulates adrenal cortex to release cortisol.
• One strength of research into the hypothalamic-pituitary-adrenal system is that it helps medical professionals to understand the effects of stress on the body over time and how to treat it.
• Weinstock et al. (1992) found that prenatal stress caused in mother rats led to changes in the rats’ behaviour, namely showing more emotional reactions in stressful situations, but seemed to cause particular issues for females, who took longer to return to their normal resting state. This matters because it indicates the importance of helping mothers avoid stress during pregnancy for the sake of their offspring.
• Some might consider that the work of researchers into the physiology of stress is reductionist. For example, with regards to the hypothalamic-pituitary-adrenal system, there is a good understanding of the biological systems involved, but not as much known about the role of cognition and emotion when someone experiences prolonged stress
• Cortisol has been linked to some negative effects in connection with stress, the main being suppression of the immune system, which is why there is a large body of research into the links between stress and illness.
• The function of the immune system is to detect foreign bodies in the organism and destroy them by travelling through the body and targeting invading pathogens (anything which can produce disease, such as viruses, bacteria or parasites).
• Pathogen carry antigens. In order to destroy pathogens, white blood cells are needed which can form antibodies.
• Ordinarily the immune system would function well, but with chronic stress, the release of glucocorticoids such as cortisol has been linked to problems with the immune system.
• Kiecoult-Glaser et al studied the link between high stress and immunosuppression in 1st year medical students. They measured this by recording the natural killer cell activity. Blood samples were taken from 75 students a month before exams and again after the exams had started. The PS also completed questionaries.
• Results of Kiecoult-Glaser : In the second samples of blood, NK cell activity was reduced and those who scored highly in the questionnaire for negative life events, psychiatric symptoms and loneliness, had the lowest activity.
• Cohen et al. (1993) exposed participants to the common cold virus and found that those with high stress scores on a questionnaire were more likely to develop the cold itself
• Kiecoult-Glaser et al. (1995) found that a group of female participants responsible for caring for elderly relatives, took over a week longer to heal from a small punch biopsy wound administered by the experimenters than an age-matched control group. This suggests that the stress of being a carer had led to immunosuppression, which meant the body was unable to heal itself effectively.
• A criticism of research into stress and illness is that much of the evidence is correlational in nature, which means that it is difficult to show cause and effect as the variables are naturally occurring
• Cardiovascular disorders (CVDs) are those which come as a result of exposing the system to extended periods of stress and can lead to a number of different conditions due to the negative impact of stress and other factors on the heart and blood vessels, such as coronary heart disease (CHD), hypertension (high blood pressure) and atherosclerosis (thickening of the artery wall).
• The relationship between stress and CVDs is seen as either direct or indirect, in that stress can lead to these conditions, or individuals with stress may adopt poor lifestyle changes
• Kamarck et al. (1990) found that female participants who were accompanied by a friend to a laboratory to complete potentially stressful tasks showed reduced cardiovascular reactivity, suggesting that social support may reduce cardiovascular risk.
• Cobb and Rose compared stress and illness rates between air traffic controllers and second class airmen. The researchers examined medical records and they found a higher rates of CVDs in the air traffic controllers .
• One criticism of research into stress and cardiovascular disorders is that it is correlational and therefore cannot show cause and effect
• A criticism of research into stress and cardiovascular disorders is that it could be seen as deterministic
• Holmes and Rahe created the social readjustment rating scale which measured life change units. PS were given several life events that had been taken from people who had illness. PS were given a baseline score of 500 from marriage. The results showed high correlation between each PS assessment and readjustment required.
• Holmes and Rahe argued that individuals who had experienced a total of 300+ life change units in the last 12 months had an 80% chance of suffering from stress