Presentation on theme: "1 Stress: the brain, body and performance PS3002: Brain & Cognition John Beech School of Psychology University of Leicester."— Presentation transcript:
1 Stress: the brain, body and performance PS3002: Brain & Cognition John Beech School of Psychology University of Leicester
2 Stress: the brain, body and performance Introduction: Types of stress: 1. Physiological – The SAM & HPA systems, the GAS syndrome (Selye), effects on health, especially immunity. 2. Performance (a) Cognitive – Yerkes-Dodson, effects on memory & concentration. (b) Behavioural – Absenteeism, sleep disorders 3. Emotional – physical tension, anxiety & depression Interventions 1. Transactional stress-coping 2. Stress inoculation 3. Biofeedback 4. Social Support 5. Drugs
3 Defining stress Stress is hard to define because it depends on the situation. Hans Selye* (1956) suggested that stress was the rate of wear and tear caused by life, implying that if you have a lot of stress for a long period, your body will reflect the consequences. Individuals vary in their responses to stress, so the extent to which that individual’s body reacts to stress could be considered to be what stress means to that particular person. There are different types of effects of stress as follows… [*pronounced Sell-yay]
4 Introduction: the effects of stress 1. Physiological effects – the body responds: Adrenaline & noradrenaline released Digestive system closes – stomach feels queasy Air passages in lungs expand – respiration increases Heart rate increases Blood vessels constrict Pupil dilation 3. Emotional Increasing psychological tension Anxiety & depression Increasing physical tension – muscles ache 2. Effects in Performance (a) Behavioural effects –Absenteeism increases and work performance reduced –Sleep disruptions (b) Cognitive –Easily distracted/poor concentration –Reduced STM capability
5 Stress: physiological effects Satcher (1999) “We know that 50% of deaths are directly related to human behaviours, and yet we spend too little time doing research and implementing programs related to them” (the US Surgeon General). We need to understand how our bodies respond to stress, starting first by looking at what happens when we respond to danger.
6 The activation of two systems: SAM and HPA** Stressor hypothalamus Immediate effect Activates SAM – the Sympathetic Adrenal Medullary system. Activity in the sympathetic part of the ANS stimulates the adrenal medullary system* Produces adrenaline & noradrenaline Arouses the sympathetic branch of the ANS & reduces activity in the parasympathetic system. (*part of adrenal glands) Longer term effect (hours +): HPA** SAM consumes resources – so countershock to reduce damage The hypothalamus produces corticotropin- releasing factor (CRF) Activates anterior pituitary gland Releases ACTH*** – stimulating the adrenal cortex producing cortisol Gives steady supply of glucose and suppresses the immune system (**hypothalamic-pituitary-adrenocortical axis;*** ACTH = corticotropin )
7 Effects of stress on health The physiologist Walter Cannon (1929) first suggested the term ‘flight or fight’ for our reactions to stress. He proposed the thalamus was the important part that simultaneously caused both emotional and physiological responses. But now the thalamus is not considered to be particularly important. He also noted that these effects are irrespective of the type of threat (e.g. fear, trauma, a bad incident, etc.)
8 Effects of stress on health General Adaptation Syndrome (GAS) – Hans Selye ( ) Selye was an Hungarian-born Canadian. He proposed 3 stages of GAS: 1. Alarm reaction – the body prepares for ‘flight or fight’ – this is not a sustainable condition. The sympathetic nervous system is increased leading to the release of hormones from the adrenal gland. We have all the physiological responses we mentioned (e.g. to pulse rate, breathing etc). (Like the SAM system.)
9 Effects of stress on health General Adaptation Syndrome (GAS) – Hans Selye 2. Stage of resistance Signs of strain emerge and we experience increasing psychological disorganisation. Coping mechanisms are intensified. But if the stress is long-lived we resort to inappropriate coping techniques – probably too rigidly. This depletes emotional resources further. Signs of wear and tear appear. This stage is known as adaptation, and as already described, leads to elevated levels of homeostasis*. *(homeostasis = maintenance of equilibrium by adjusting physiological processes)
10 Effects of stress on health General Adaptation Syndrome (GAS) – Hans Selye 3. Stage of exhaustion We continue to use defence mechanisms that are getting more ineffective. Some lose reality. Others have ‘burnout’ – inability to concentrate, delay, irritability, nothing worthwhile. Can turn to alcohol, drugs, get skin or stomach problems. If this continues may produce irreparable damage.
11 Effects of stress on health - GAS If this third stage keeps going then this produces ‘accommodation’. Biologically this means that the response of a biological object in the face of a constant stimulus decreases over time. For example, the athlete’s training for a sustained period eventually leads to a plateau in performance. To avoid this the athlete needs to vary training and also take some rest. This is a multileveled model. If there is rest from the stimulus (the stressful experience) can allow adaptation. This can be viewed positively if the graph is thought as a training schedule in which the body is being physically trained, but not so good (or even disastrous) if it is seen as physiological responses to continuing stress.
12 Effects of stress on health - GAS Cortisol helps the body to come to terms with stress during this phase. In more extreme cases of stress, glucocorticoids are produced attempting to restore homeostasis, but this also depresses the immune system. (Glucocorticoids also have anti- inflammatory properties.) Selye proposed a ‘hypothalamic-pituitary’ axis as the key brain system and now this is referred to as the LHPA – ‘Limbic-hypothalamic-pituitary axis’ by many although Michael Eysenck refers to the hypothalamic pituitary-adrenocortical axis (HPA). So how can physical stress lead to health problems?...
13 Effects of stress on health - GAS The effects Stress makes the heart, lungs, nervous system and other systems work harder. But prolonged exposure to these systems can lead eventually to physical disorders. Stress powerfully affects the immune system and sustained stress can destroy this capability to protect against disease. The coping behaviours of smoking, alcohol use, overeating, not exercising further reduces healthiness. The evidence There is mounting evidence for the effects on both the brain and the body, so we will only sample some: Cortisol (mentioned as active in the exhaustion stage) can damage hippocampal cells and therefore affect learning and memory (Newcomer et al. 1999; Sapolsky, 1992).
14 Effects of stress on health The evidence for stress affecting health (continued) Cortisol also increases blood pressure, which weakens the walls of blood vessels, can trigger erratic heart beats, increase cholesterol (leading over time to hardening of the arteries). Life stresses and social isolation have been shown to predict subsequent heart attacks (Ruberman et al. 1984). The well-known ‘Type A’ personality has been shown in several studies to predict coronary heart disease (CHD). This type reacts with impatience, hostility to events and is always striving. Similarly, people who scored high on an anger scale were 2.5 times more likely to have a heart attack (Williams et al, 2000) But others have suggested that it is more lifestyle (e.g. more smoking and drinking) that is important.
15 Effects of stress on health The evidence for stress affecting health (continued) Bosch et al showed how stress affected immunity by looking at the concentration of immunoglobins in the saliva. These are the first line of defence that pathogens* have to cross. They found that undergoing a timed memory task activated this factor (increased immunity) whereas watching a violent video weakened immunity. So stress can have differing effects on immunity. (*= agents causing disease, especially bacteria.)
16 Effects of stress on health The evidence for stress affecting health (continued) Even chronic low-level noise from local traffic can potentially affect health. Evans & Lepore, 1993 found that such noise increased levels of stress hormone cortisol in children (total N = 115), including slightly higher blood pressure and raised heart rate. The symptoms included anxiety and nervousness. Half the children lived in quiet areas in Austria ( 60 dB e.g. raised voices). So exposure to the sounds from roads and trains can be a stressor.
17 Effects of stress on health The evidence for stress affecting health (continued) The effects of negativity Peterson, Seligman & Valiant (1988) found that pessimistic men were twice as likely to have chronic disease than their optimistic Harvard classmates 20 years later. Barefoot et al. (1983) found that hostility predicted heart disease and overall mortality over 25 years. Depression (producing long-term stress) also increases the risk of heart disease (e.g. McCabe et al. 2000). However, these effects are not necessarily so stark, Booth-Kewley and Friedman (1987) in a meta-analysis found only a low correlation of 0.14 between anxiety and heart disease. Other studies have found no association in the long term between negative affect and overall mortality (e.g. Shekelle et al., 1981).
18 Effects of stress on health - the field of psychoneuroimmunology (PNI) This field examines the interaction between stress versus nervous system activity, the immune system and the endocrine system. In a later study (Cohen, 2003) it was shown that those who’d had a lot of positive emotions (relaxation, happiness) were less likely to get colds. The association between psychological stress (low = below median and high = above median) and symptoms of upper respiratory illness among subjects infected with an influenza A virus. Viral inoculation occurred at the end of day 0. SEs are indicated. (Cohen et al.1999 – PSS = 10-item Perceived Stress Scale, Cohen et al 1983)
19 Effects of stress on health: the evidence (continued) There are many such studies, including ones already described. An important aspect of the immune system is two classes of white blood cells: B cells (which mature in the bone marrow) and T cells (which mature in the thymus – located behind the top of the breastbone/lower part of neck). The natural killer (NK) cell is important for detecting and destroying precancerous cells. So if certain types of white blood cells are killed by a stress response then infection and tumour growth may be stimulated. So many studies look at the number of NK cells in the blood as an index of the immune system. Glucocorticoids released during stress hinder the formation of white blood cells such as the NK cells.
20 Stress and performance Researchers have often used arousal theory as a means of explaining stress on performance. In particular the Yerkes- Dodson law has been prominent. This suggests that we operate best at moderate levels of arousal. Increasing our arousal beyond this leads to reduced performance. An increase in stress level by an agent (e.g. noise, drugs) results in the curve shifting to the right. This shift may not necessarily be stressful, e.g. incentives might be used. The Yerkes-Dodson Law was originally used in the context of motivation (‘drive’). Duffy(1962) proposed increasing electrocortical states, from left to right with lowest activity in the left: delta theta alpha beta But there have been problems in reliably showing this by psychophysiological techniques.
21 Stress and performance Wilkinson (1963) provided data relevant to the Yerkes-Dodson hypothesis looking at the effects of noise and sleep deprivation. The numbers in the cells of the table illustrate increasing levels of arousal. So the condition of lowest arousal (1 in the table) would be being sleep deprived and carrying out an experiment without any noise. Whereas the highest level (4) would be people who’d had normal sleep and who had experienced noise. The task was a continuous reaction time task and accuracy of performance was monitored. Quiet (low) Noise (higher) Sleep deprived (low) 12 Normal sleep (higher) 34
23 Stress and performance The results showed an inverted-U effect with the 3rd condition (those with nomal sleep and quiet conditions) producing the highest accuracy on the experimental task. Easterbrook (1959) explained the Y- D law by suggesting an analogy with an internal searchlight for the focus of attention that narrows as arousal goes up. This results in the attended stimuli continuing to be processed optimally, but irrelevant stimuli to be rejected. But with further increases in arousal the focus become too narrow and even the performance with the attended stimuli suffers. In this hypothesis, with increased task difficulty we need a widened focus of attention (compared to easier tasks), but unfortunately the focus actually narrows, leading to poorer performance at a lower level of arousal. A lot of experiments generally show that changing arousal does influence attention between primary and secondary sources. There are issues: (e.g. Eysenck, 1982) (1) is this process automatic or voluntary? and (2) it probably can’t apply to more complex tasks, such as when attention and memory interact. The Y-D concept has come under a lot of criticism overall.
24 Stress and performance Criticisms of Yerkes-Dodson 1.Problems of measurement. There have been unsuccessful attempts to relate arousal to measures such as pulse rate and skin conductance, but these don’t correlate with each other. So there appears to be no successful measurement as yet. Similarly, there is a lack of relationship between anxiety scales and psychophysiological measures as a means of measuring arousal. 2.There could be several arousal systems. E.g. There could be different arousal systems for nicotine and amphetamine, which each affect different neurotransmitter systems. There is no consensus on how these interact. 3.Lack of consistency. When individuals are in conditions of extreme arousal the effects are weaker than might be expected.
25 Stress and performance Effects of stress on memory Bremner et al. (1993) compared Vietnam veterans who had combat- related posttraumatic stress disorder (PTSD) with matched controls and found that the veterans had problems with immediate and delayed recall of verbal information, but there was no difference in IQ. In severe cases an emotional shock can cause amnesia. Treatment initially for a traumatic event can be sedation and plenty of care. Cases are occasionally reported in the news. This is known as dissociative amnesia in which there is a loss of substantial important personal information, perhaps on more than one occasion. This is usually traumatic in origin and so can’t just be explained by forgetting. A rare instance of this is when an individual suddenly leaves their home and sets off on a journey that can last hours, days or even months. They can be confused about who they are. Related to this can be anxiety disorders and PTSD. Treatments – therapy is designed to restore lost memory ASAP. Hypnosis or medication can sometimes be useful in recalling identity. Psychotherapy would help the individual cope with the underlying trauma.
26 Cases of amnesia May 16 th 2005 – this appeared in the press. The mysterious “piano man” was found wandering on the Isle of Sheppey. On the right is his sketch he gave to hospital staff. He subsequently played melancholic music on a piano after it was provided for several weeks – without uttering a word. By August he was flown back to his native Germany – but there is speculation now that it was an elaborate hoax! Agatha Christie is a famous example when she disappeared to a hotel in Halifax in 1926 and afterwards she said that she’d suffered amnesia. She had checked in under the name of her husband’s mistress.
27 Cases of amnesia On July 3, 2003 Doug Bruce walked into a police station saying that he didn’t know who he was. Eventually, through contact with family and friends he found out his identity. But so far, he remembers nothing of his past. This was featured in 2006 in a TV documentary “Unknown White Male”. In his case his episodic memory appears to have been wiped out, and a lot of his semantic memory, but his procedural memory seems relatively unaffected. For instance, he could sign his name, but it was not legible apart from the beginning “d”. He could speak English and French. Was it induced by stress? Possibly. It is likely that his memory will eventually recover. A question still remains whether this too could be a hoax case.
28 Stress and performance Effects of stress on memory (continued) Why should stress affect memory? In the more extreme cases there is an over-production of cortisol, secreted by the adrenal glands. This may prevent the establishment of new memories as well as impairing retrieval of what is in memory. Sapolsky (1992) has suggested that this sustained production of cortisol actually damages the hippocampus. Cortisol stays in the system much longer than adrenalin. In addition the hippocampus is an early mechanism to suffer problems in ageing – possibly due to the sustained influence of cortisol induced by stress. Stauth & Khalsa (1999) suggest that in normal functioning the hippocampus, more than other brain areas, secretes a hormone that eventually switches off cortisol production. However older people have lost 20-25% of hippocampal cells, so this feedback is impaired. The cortisol production continues producing further damage to the hippocampus.
29 Stress and performance Disturbed concentration – this is the other (cognitive) symptom of stress (the other being problems in memory). McFarlane et al. (1993) using ERPs (event-related potentials) compared PTSD patients with controls in a task that had to discriminate tones. The PTSD patients had considerable difficulties selectively attending to the target tones. McFarlane et al. proposed that PTSD patients had a dysfunction in their noradrenaline function, which has a crucial role in selective attention. This resulted in slowed RTs and is probably also linked to the impairments in memory shown in PTSD patients.
30 Stress and behavioural performance Behavioural manifestations As mentioned before stress can produce problems in the following areas: 1.Absenteeism from work 2.Sleep disruption 1. Absenteeism In 2004 in the UK a survey revealed that 52% of businesses had had an increase in absenteeism due to stress.
31 Stress and behavioural performance 1. Absenteeism (continued) Woo et al. (1999) compared working conditions in which there were poor environmental stressors (e.g. uncomfortable temperature working in a kitchen) with there were psycho-social stressors (high workload, dysfunctional work tensions). They found that more days were taken off for mild illnesses for environmental stressors compared to psycho-social stressors. On the other hand, when the psycho-social stressors were high people were more likely to report minor illnesses, but not actually take time off work. So absenteeism relates to stress only in terms of the physical work conditions. However, actual productivity is unlikely to be helped when there are poor psycho-social conditions, if it means there is going to be more minor illnesses while people try to keep on working instead of taking rest.
32 Stress and behavioural performance 2. Sleep disruption States et al. (2003) have suggested that chronic sleep disruption is the major symptom in the PTSD patient. They further suggest that if left untreated that this could lead to long term damage in brain physiology. To overcome this they suggest the application of drug therapy. They reviewed 7 clinical cases of PTSD with the treatment of Olanzapine. As a result of such treatment all patients had improved sleep and there was also improvement in other PTSD symptoms. It is perhaps difficult sorting out cause-and-effect – does stress cause loss of sleep or loss of sleep lead to stress – however… Disturbed sleep, measured by no. of hours of sleep lost, can lead to higher risk of heart attacks and age-related symptoms such as Type 2 diabetes. This is to to due hormonal imbalance especially in the cortisol rhythm. Also, melatonin, produced during sleep, is an anti- oxidant that prevents DNA damage. Disturbed sleep reduces its effects.
33 Stress and emotional effects Stress can lead to: 1.Anxiety and depression 2.Physical tension 1. Stress and anxiety and depression Stress and anxiety are interrelated in that situations, or your own thoughts, can make you frustrated or anxious. The extent to which you have these reactions is described as stress. The symptoms of anxiety are perspiration, trembling or twitching, muscle tension (including headaches), dry mouth and stomach ache. There can be accompanying physiological symptoms, such as dizziness, diarrhoea, irritability, lack of sleep and so on.
34 Stress and emotional effects Anxiety and depression (continued) In the case of depression, there can be a certain degree of circularity – stress may lead to depression and the state of being depressed means that one copes poorly with day-to-day stresses. The incidence is 1 in 4 women and 1 in 10 men will suffer depression at some point in their lives. It is believed that women are more prone due to greater hormonal changes. However, situational circumstances may be a contributory factor as well. From a biochemical viewpoint there appears to be under-activity in the frontal cortex and over- activity in the limbic system. But life events can also be a trigger. On the other hand, some individuals appear to be more prone to depression. Depression Reduced coping Stress
35 Stress and emotional effects 2. Stress and physical tension Groups of muscles (in the shoulder, neck and head) tend to tighten in response to stress, which over time becomes painful. Consequently physical tension can be reduced by focussing on these muscle groups. Most would agree that tension headaches are the result of continued contraction of the pericranial muscles*. Pain is very difficult to evaluate in these circumstances, for example, is this due to faulty posture, or is one more sensitive to pain because of emotional state? Carlsson et al. (1990) in Sweden compared 2 treatments for chronic tension headaches (which had persisted on average for 9 years) involving either acupuncture or physiotherapy. Both groups improved for 7-12 months after treatment, with the physiotherapy group having the edge in terms of reduction of intensity of headache and in overall well-being. [*muscles in the outer surface of the skull]
36 Stress and emotional effects Stress and physical tension (continued) In the Carlsson study the physiotherapy consisted of helping them (1) to understand the factors leading to headaches – psychosocial stress, muscular stress, drug overuse; (2) showing that pain can be relieved without analgesics, instead showing them how to use relaxation, auto- massage, cryotherapy* and Transcutaneous** Electrical Nerve Stimulation (TENS); (3) smoothed stretching of the contracted muscles; (4) broader information was given on body awareness during stress, allowing enough time for rest and sleep. Thus although the physiotherapy was a central part, there were other aspects that were covered too. These other aspects do not appear to have been given to the acupuncture patients. [*cryotherapy = using low temperature;**transcutaneous = through or by way of the skin]
37 Stress: the brain, body and performance Topics that have been covered Types of stress: 1. Physiological – The SAM & HPA systems, the GAS syndrome (Selye), effects on health, esp immunity. 2. Performance (a) Cognitive – Yerkes-Dodson, effects on memory & concentration. (b) Behavioural – Absenteeism, sleep disorders 3. Emotional – physical tension, anxiety & depression Still to be covered Interventions 1. Transactional stress-coping 2. Stress inoculation 3. Biofeedback 4. Social Support 5. Drugs
38 Interventions to alleviate stress There do seem to be effects of stress on health and on performance. What kinds of interventions would be worthwhile for the practitioner, support agencies or the individual to try out? We shall look at this under 5 main headings: 1.Transactional stress coping 2.Stress inoculation 3.Biofeedback and relaxation 4.Improving social support 5.Drugs
39 Person demands Environmental Outcome Symptoms of stress Interventions to relieve stress: transactional stress- coping Transactional stress-coping model This is perhaps more a model than an intervention that is not confined to psychology and is used in medicine and in the social sciences. For example in the field of diabetes, a patient has to cope with their own qualities (e.g. gender, SES, age, personality) and the support that they hope to get from others (family, friends, social organisations) and into the melting pot are important life events (job loss, family death, divorce, separation, etc.) Subsequent quality of life is an outcome that the patient adjusts to along with glycemic control. A more general model is illustrated on the right.
40 Interventions to relieve stress: transactional stress-coping Matthews (2000) suggests that a person’s subjective response in a situation is based on their cognitions and the environmental demands. If a task is seen as overloading then this is distressing. On the other hand tasks seen as challenging promote engagement. These conclusions were based on work in which people had to complete a stress state questionnaire examining motivational, emotional and cognitive responses. Stress was equated with negative aspects of these 3 entities: lack of motivation, emotional tension and intrusive thoughts.
41 Interventions to relieve stress: transactional stress-coping Conclusions on the transactional model Such work moves the focus away from a single dimension of arousal/stress. Instead something like the transactional model may be more reflective of brain structures. Transactional theory acknowledges that the way individuals perceive their environment is a critical facet of any stress that they may experience. It may also be a way forward for practitioners in helping people to cope with stress.
42 Interventions to alleviate stress: stress inoculation Cognitive therapy is used for anxiety and depression whereby irrational and negative thoughts are replaced. Meichenbaum (1985) suggests that instead of applying this just to extreme cases, it should be used earlier. He developed stress inoculation training to be done in 3 phases: 1.Assessment – the problem is discussed and the person’s views on how to get rid of it are taken into account. 2.Reduction of stress - relaxation techniques are learned. Self-coping statements are learned: 2a. Preparing for a stressor – (“Suppose X happens – what should I do?”) 2b. Confronting a stressor (“Start deep breathing…”) 2c. Coping with feeling overwhelmed (“try to reduce it to manageable level…”) 3.Application and follow through These techniques are used in different scenarios and perhaps used in role play. Then used in real life. Finally, as a technique it appears to be an effective treatment – probably when it can effectively transfer easily to new situations.
43 Stress reduction training: Meichenbaum (1977) – from Eysenck Assessment Stress reduction techniques Application and follow-through What’s the Problem? Relaxation Self-instruction Imagine and role-play Stress-reduction techniques “Keep calm, I can cope” There’s no point in worrying” Apply in real life context
44 Interventions to alleviate stress: biofeedback Biofeedback – definition A person is given ongoing information about some aspect of their physical functioning. E.g. EMG (electromyograph) on the forehead can give auditory feedback on muscle tension. Similarly a GSR (galvanic skin response) can monitor and give feedback on the degree of perspiration due to tension. Training is given for relaxation. Three stages of feedback 1.Awareness – getting insight into that physiological response (e.g. pulse rate, tension in a particular area). 2.Gaining control – learning in a peaceful place how to control. This might include rewards for success. 3.Transfer into real life.
45 Interventions to alleviate stress: biofeedback The autonomic system controls various aspects of our functioning – heart rate, blood pressure, skin temperature and brain waves. These are all aspects that we can’t directly control. However, with biofeedback we can exert indirect control over these by such activities as relaxation and deep breathing. Evidence On the positive side several laboratory and clinical studies report positive effects. For example, a review by Blanchard (1994) concludes that biofeedback can reduce blood pressure. On the negative side: We don’t know why it works. Some effects may just be due to relaxation training, or due to inducing a sense of control. It doesn’t seem to be likely to work for those who have a “driven” way of living.
46 Interventions to alleviate stress: Social support This is a popular suggestion in magazines for combating stress – that one needs a “social network”. There is a distinction between structural and functional social support. Structural support is the basic network and functional support is about the quality of that network. It is functional support that appears to be important to health and well-being. Whereas a large structural network can have a negative effect if it is very time consuming to maintain (Shaefer et al. 1981). E.g. a review by Uchino et al. (1999) showed that blood pressure was lower for those with high levels of social support. They conclude: “Social support may influence mortality via changes in cardiovascular, endocrine and immune systems”.
47 Interventions to alleviate stress: drugs People going to their GP to alleviate stress can be prescribed a drug. Here are the most common types: Benzodiazepines- (e.g. Valium, Librium) – they are effective and are used by millions. But they have side effects – they can act like sedatives. Can cause memory problems, depression and interact with alcohol. Higher probability of accidents. Dependency – of those taking for at least 1 year, only 43% managed to stop for at least a week. Buspirone – has advantages over the benzodiazepines. It helps the effects of serotonin and doesn’t act as a sedative or have marked withdrawal problems. But its side effects are headaches and depression. It is less effective with severe stress as it takes 2 weeks to take effect.
48 Interventions to alleviate stress: drugs (continued) Beta blockers – these reduce activity in the sympathetic nervous system by reducing heart rate and lowering blood pressure (helping treatment of heart disease). This affects the body, rather than the brain. Lau et al. (1992) showed that they reduced death risk by 20% for those with heart disease. There are no dependence problems. Side effects include cold extremities, hallucinations and tiredness. Summing up on drugs for stress - clearly professionals and patients find drugs useful for reduction of intense stress. But the causes of the stress are not dealt with directly (e.g. life style, etc.) Also they can have side effects. E.g. Ashton (1997) recommends that benzodiazepines should only be used for 4 weeks AND only to those with severe symptoms AND only minimal dose. Those already dependent, should have the dose reduced. 70% of dependent users who are motivated, can give them up for several years.
49 Stress: the brain, body and performance Topics that have been covered Types of stress: 1. Physiological – The SAM & HPA systems, the GAS syndrome (Selye), effects on health, especially immunity. 2. Performance (a) Cognitive – Yerkes-Dodson, effects on memory & concentration. (b) Behavioural – Absenteeism, sleep disorders 3. Emotional – physical tension, anxiety & depression Interventions 1. Transactional stress-coping 2. Stress inoculation 3. Biofeedback 4. Social Support 5. Drugs
50 Concluding remarks As we have seen stress is a condition that is produced by a number of factors, and it can have serious underlying biological consequences. Academics argue about some of the main concepts such as the inverted U-shaped effect of performance as a function of arousal; but the clinical manifestations of stress and anxiety are fairly clear: there is an association between stress and many physical and mental problems. Related to this, the immune system is implicated but there is some ambivalence in the actual findings, suggesting that the relationship, for instance, between type A and heart disease is not a strong one. The impact of everyday events varies across people, but certain people appear to be more sensitive to these stressors. Are these real or just more exaggerated? Various therapies have been outlined that can lead to improvements in people’s condition. The evidence appears to suggest that there is likely to be more long-term success if people can learn to take control of their stresses by learning appropriate techniques and at the same time try to wean away from a dependence on drug treatments.