Stress

Stress

1. Acute Stress

   • Automatic nervous system (ANS)
     • Parasympathetic branch
       • returns the animal to a state of relaxation.
     • Sympathetic nervous system (SNS)
       • arouses an animal to be ready for fight or flight
       • sympathetic adrenal medullary system (SAM)
         • alerts the animal through the release of adrenaline into the bloodstream
           • it is transported rapidly throughout the body to prepare the animal for fight or flight.
         • is regulated by the SNS and adrenal medulla.
       • SNS and SAM make the sympathomedullary pathway
       • neurones fron the SNS travel to virtually every organ and gland in the body
         • prepares the ody for the rapid actio necessary when an animal is under threat
           • increases heart rate
           • increases blood pressure
           • increases pupil size
           • mobalisation of fat and glycogen in the bloodstream
       • releases noradrenaline
         • the neurotransmitter released by the SNS to activate these internal body organs.
     • governs itself
     • needed for some bodily functions
       • they may not work as well as they need to if you had to think about them
   • adrenal medulla
     • neurons of the SNS travel to the medulla
       • so that when it is activated it releases adrenaline into the bloodstream
     • once in the blood, adrenaline has widespread effects on the body's physiological systems

2. Chronic Stress

   • hypothalamic-pituitary-adrenal axis (HPA)
     • the body's stress system
     • controls levels of cortisol (CORT)
     • activated by both physical and emotional stressors
     • harder to activate than the SAM
   • Hypothalamus
     • stressors are perceived by the brain
       • message is passed to a small cone-shaped part of the brain
         • This is the hypothalamus
     • the control system for most of the body's hormonal systems
       • including those involved in the stress response
     • paraventricular nucleus (PVN)
       • leads to the production of a chemical messenger
         • corticotrophin-releasing factor (CRF)
   • on arrival at the anterior love of the pituitary gland, CRF causes the pituitary to produce and release adrenocorticotrophic hormone (ACTH)
     • ATCH is transported in the bloodstream to the adrenal glands
       • on top of the kidneys
   • the adrenal cortex
     • cortisol is released and is responsible for several stress-related effects in the body.
       • some of these are positive
         • quick burst of energy
         • lower sensitivity to pain
       • other's are negative
         • impaired cognitive performance
         • higher blood pressure
         • lower immune response
   • process takes about 20 minutes to be completed

3. Stress and the Immune system

   • kiecolt-glaser et al
     • investigated whether the stress of short term stressors had an effect on immune system functioning in medical students
     • took blood samples one month before and during the exam period
       • was assessed by measuring NK cell activity & ppts completed a questionnaire to measure other life stressors they were experiencing
     • NK cell activity was significantly reduced in the second blood sample compared to the sample taken one month before
       • suggests that short term predictable stressors reduce immune system functioning, increasing vulnerability to illness
       • also found that those students who also reported the highest levels of loneliness had the lower NK cell activity
   • Marucha et al
     • inflicted a 'punch biopsy' in the mouth of students either during the summer holidays or three days before an exam
     • the woulds given before the exam took 40% longer to heal than the wounds during the holidays
   • relationship stress
     • Kiecolt-Glaser et al
       • tested the impact of interpersonal conflict on wound healing
         • found blister wounds on the arms of married couples healed more slowly after they had discussion which were conflicting rather than supportive
     • Malarkey et al
       • studied 90 newly-web couples over a 24-hour period
       • asked them to discuss and resolve maritial issues likely to produce conflict
         • mariatial conflict produced significant changes in adrenaline and noradrenaline, which could lead to poorer immune functioning

4. Life Changes

   • Holmes and Rahe played a large role in developing the idea that life changes are linked to stress and illness
     • in the course of treating patients, they observed that it was ofter the case that a range of major life events seemed to precede phusical illness
     • Developed the Social Readjustment Rating Scale (SRRS) based on the 43 life events taken from their analysis of over 5000 patients
       • 400 ppts were asked to score each event in terms of how mch readjustment would be required by the average person.
       • The ppts were asked to provide a numerical figure for this readjustment, taking marriage as an arbitrary baseline value of 50.
       • If an event would take longer to readjust to than marriage, then they were told to give it a larger score.
       • Scores for all ppts were totalled and averaged to produce life change units (LCUs) for each life event.
   • Rahe et al used this technique and conducted a military version of the SRRS
     • men filled the questionnaire just before a tour of duty, noting all the life events experienced over the previous six months
       • found a positive correlation between LCU score and illness score of +.118
         • men who scored low in terms of their SRE scores also had low levels of illness while at sea.
         • Those who had hight SRE scores experienced correspondingly high levels of illness
   • Michael and BEn-Zur studied 130 men and women, half of whom had been recently divorced and half recently widowed.
     • they studied levels of life satisfaction
       • In the widowed group this was found to be higher before their bereavement than after the loss.
         • Divorced individuals showed the opposite pattern after separation from their partners, and had higher levels of life satisfaction

5. Daily Hassles

   • Delongis et al developed the Hassles and Uplifts Scales (HSUP)
     • measures respondents' attitudes towards daily situations and provides a way of evaluating both the positive and negative events that occur in life
   • Bouteyre investigated the relationship beween daily hassles and the mental health of students during the transitio period from school to university
     • ppts completed the hassles part of the HSUP and the Beck Depression Inventory
     • Results showed that 41% of the students st6udied suffered from depressive symptoms
       • positive correlation between scores on the hassles scale and the incidence of depressive symptoms
   • Gervais asked nurses to keep diaries for a month
     • recording all their daily hassles and uplifts at work and to rate their performance over the same period
       • Daily hassles were found to increase job strain and decrease job performance
   • Flett found that major life-changing events may differ from daily hassles.
     • in the extent to which a person would receive and/or seek social support
       • A total of 320 students need a scenario describing a male or female individual who had experienced either a major life event or daily hassles
         • individuals who had suffered major life events were rated high in both seeking and receiving support from significant others.

6. Workplace Stress

   • Marmot investigated the job-strain model of workplace stress
     • 7372 Civil servants working in London agreed to answer a questionnaire on workload, job control and amount of social support
       • and to be checked for signs of cardiovascular disease
     • found no link between hig workload and stress-related illness
   • Johansson looked at the effects of performing repetitive jobs that require continuous attention and some responsibility
     • The sawyers in a Swedish sawmill have a stressful job - repetitive tasks, which an unrelenting pace and a sense of responsibility for the company
       • the high-risk group were found to have higher illness rates and also higher levels of adrenaline in their urine than a low risk group
       • high risk group also had higher levels of stress hormones on work days than on rest days
   • Five years later Marmot found that those who had initially reported low levels of job control were more likely to have developed heart disease

7. Personality factors and stress

   • Type A behaviour
     • - Competitiveness and achievement striving
     • - Impatience and time urgency
     • -Hostility and aggressiveness
     • These characteristics lead to raised blood pressure and raised levels of stress hormones
       • both linked to ill health, particularly the development of coronary heart disease (CHD)
     • Friedman and Rosenman
       • 3000 men aged 39 to 59 living in California, were examined for signs of CHD and personalities were assessed by interview
       • After 8 1/2 years twice as many Type A ppts had died of cardiovascular problems
   • Type B
     • patient
     • Relaxed
     • easy going
     • much less likely to develop CHD
   • Hardy Personality
     • Control - Hardy people see themselves as being in control of their lives
     • Commitment - Hardy people are involved with the world around them, and have a strong sense of purpose
     • Challenge - Hardy people see life challenges as problems to be overcome rather than as threats or stressors

8. Stress Inoculation Therapy (SIT)

   • developed by Meichenbaum
   • Cognitive Behavioural Therapy designed to deal with stress
   • individual should develop a form of coping before the problem arises
   • Conceptualisation phase
   • Skills acquisition phase and rehearsal
   • Application phase

9. Drug Therapies

   • Benzodiazepines (BZs)
     • enhance the action of GABA
     • allows more chloride ions to enter the neuron
     • brain's output of excitatory neurotransmitters is reduced, and the person feels calmer
   • Beta-blockers (BBs)
     • sympathetic arousal
     • bind to beta-receptors on the cells of the heart and other parts of the body that are usually stimulated during arousal
     • cause the reverse effect of stress hormones, causing the heart to beat more slowly and with less force.
     • person feels calmer and less anxious
     • blood vessels contract less