Chapter 1: The ins and outs of the mind's effects on the body

- A stressor  is every possible threat to the attainment of psychobiological goals. 

A stress response is an adaptive psychobiological reaction to a stressor.

- The working definition of a stress response: a negative emotional response, which is psychobiological in nature.

- A lot of diseases have a higher chance of occurrence when organisms are chronically stressed.

- Sapolsky deals most with psychobiological routes of stress, the direct routes, via an intermediate pathogenic state, leading to diseases. We should not forget about the indirect route of stress; stress leads to poor health behavior.

- Prolonged stress may co-determine psychological disorders; depression, PTSD, etc. Mental health problems influence cognitive capacities, which influence health behaviors again.

- When your primary appraisal of a situation is threatening; you’ll have an acute stress response. When after a while you feel like coping with the situation is beyond your capabilities, your secondary appraisal (appraisal of your coping options), this leads to a chronic stress response. If this prolongs long enough, the chronic stress can lead to disregulation in the body, and eventually to disease.

- Stress is a very old functional response of the body, from a molecular level (a germ) to the macro-social level (economic crisis). 

- However, different stressor types and different personality types respond different in magnitude and duration; they can differ quantitatively. 

- Basal psychological stress factors can be divided into three stressor dimensions (1. adversity or nature of the threat 2. uncontrollability and unpredictability; the psychological core of stress and 3. duration of the response), and two response patterns (1. defence and 2. defeat). 

- The basal response pattern of defence refers to the ‘fight or flight’ response; and it is activated when there is decreased control over one or more stressors.

Defeat is what happens when there is a loss of control over stressors; we withdraw and conserve energy.

- When we feel stress, our body reacts in the same way as when it would with the exercise response; heart rate goes up, blood pressure goes up, etc.

- There is however a quantitative difference between the stress response and the exercise response: during the stress response the exercise response is amplified. A qualitative difference: Our body responds as if we are preparing for vigorous action.

- Main messages of this chapter:                      

• Brief stress response is good; it is an emergency response and functional. Prolonged or frequent stress responses are bad; not functional and lead to disease.
• The stress response is phylogenetically old; which implies that it is generally the same for all animals including humans. The stress response is a functional reaction to any conceivable threat.
• The psychological core of stressors is their uncontrollability and/or unpredictability.
• The function of the biological stress response (‘fight or flight response’) is to: 1. transport more oxygen and fuel muscles 2. save fuel and building material by suppressing other bodily activity 3. limiting damage and negative sensations.
• Stress response in humans: preparation but without action.

- Biological vulnerabilities that can make a person more prone to develop a disease are; heritable factors, acquired bodily conditions (pregnancy, old age) and disease agents (viruses). Physical vulnerabilities can be, for example, a dangerous chemical environment. Psychological vulnerabilities are psychological stressors such as poor socio-economic conditions, health cognitions (symptom perception; interpretation of bodily signals, and beliefs about risks) and health behavior (alcohol, drugs, smoking).

- Psychological factors often co-determine health problems.

- Stressors can either be psychological traumas, life changing events, daily hassles or chronic stressors.

--> Psychological traumas are the most severe. PTSD can be developed.

--> Life changing events require adaptive skills.

--> Daily hassles predict illness even better than life changing events. Daily hassles are often unpredictable as well as uncontrollable in nature.

--> Chronic stressors, worry and rumination, together with daily hassles, seem to cause the most stress. Worry and rumination are often considered a response to stress. However, they are cognitive representations of stressors: we respond to stressors that have not occurred and sometimes will not occur at all. That is why worry and rumination are also considered to be stressors.

- A (stressors) --> B (psychophysiological responses) --> C (disease).

Mediators are crucial parts in a causal chain leading from a primary cause; the stressor, to a final effect; the disease. However, modulators are factors that are not part of the causal chain, but co-determine the effect on C via their effect on B.

- Modulators can be availability of social support, appraisal, outlet for frustration and personality. 

1. The absence of social support, and especially loneliness, has direct negative effects on health. It also indirectly effects our health, because healthy lifestyles are not stimulated when there’s a lack of social support and social support buffers the effects of any stressor.

2. Psychologists often consider that the availability of an outlet for frustration makes sure that when people feel stressed, they will feel better after expressing this. There are two counterarguments: Theoretically, as long as the threat is present, our body will have a stress response. Pouring out your frustrations does not remove the threat. Secondly, through empirical evidence we know that ‘venting your emotions’ only helps when you turn them against the source of your frustrations; the threat itself. Subjects in Hokanson’s experiment were only able to lower their blood pressure by giving painful shocks to the harasser and not if it was directed towards another person. Also, as became apparent from Bushman’s experiment, we only increase our aggression when we e.g. hit a pillow intended to decrease our aggression. So, venting anger only feeds the anger.

3. A hostile personality type (Type A personality) is linked to higher risks of disease; and especially CVD. In relatively normal situations, hostile personality types feel threatened and become hostile.

Chapter 2: Negative emotions, physiology and disease risk

- Pathological forms of anger, anxiety and depression are the three general negative emotions that - in combination with stress - can increase the risk on diseases.

- Of these emotions, anger generally receives the least attention; because it is not officially considered a disorder.

- Anxiety and fear are associated with flight responses; anger is linked to fighting and depression with withdrawal. If these emotions are pathological, these action tendencies will be chronically activated in the body; which can wear the body out. Dysregulation of the immune system, high blood pressure leading to damage to the blood vessels, diseases in various organs, et cetera, are the consequences.

- Negative emotions activate the sympathetic adrenal medullary system (SAM) and the hypothalamus pituitary adrenal cortical system (HPAC).

• SAM responses involve sympathetic increases and parasympathetic decreases, and an increase of adrenalin in the blood.
• HPAC responses involve increases in primarily cortisol.

- Cardiovascular diseases can result from chronic activation of the SAM and HPAC; high blood pressure --> blood cell clotting --> heart rhythm dysregulation --> blood vessel infection.

- Infectious diseases can result from sustained activity in the SAM and HPAC.

- Autoimmune diseases can be co-determined and maintained by the SAM and HPAC.

- Negative emotions also lead to unhealthy behavior, which even increase the risk on somatic diseases more.

Anger, anxiety and depression leading to different risks:

Theory I: Equal initial physiological responses for different emotions

- A study by Brosschot and Thayer showed that heart rates increase equally during negative and positive emotions as compared to non-emotional moments.

- The reason for this is probably that the initial physiological response during emotions serves as an alert function. If the set values and actual values match, the organism does not respond, but if they don’t match; it will take action.

- There is neurological evidence for this: There is a ‘low’ fast road in the brain that is involved in the perception of danger and the activation of the emotional parts of the brain; especially the amygdala. There is a ‘high’ slower road that involves more elaborate processing of the potentially dangerous information. The low fast road responds quicker in a reflex-like reaction, so we haven’t had time to think about the actual danger via the high road.

Theory II: Two-dimensional models; arousal-valence / effort-control

- Arousal represents the activity and energy involved in an emotion, while valence is the ‘hedonic’ value of that emotion; so the negative or positive nature. These two dimensions are thought to be orthogonal and can be represented in a two-dimensional space.

- The two dimensions can also be effort and control. The effort-axis is related to the activity of the SAM system and adrenalin, and the control-axis is related to the activity of the HPAC system and cortisol.

- A model from animal psychophysiology distinguishes the flight-fight axis (aggression, defence, SAM activity) and the conservation/withdrawal axis (defeat, loss of control, HPAC activity).

- What is wrong with these two-dimensional models is that SAM and HPAC activity are seen independently. Due to the slower secretion of cortisol in the blood during emotional challenges this may have been overlooked in many studies.

- What is actually quite good about the theory of two-dimensional models is that it states that the more effort (or demand) a situation requires, the higher the disease risk. This also explains that depression is found to have a lower cardiovascular disease risk than anger and anxiety: It is less demanding.

Theory III: Anger with challenge and anger with threat

- Blascovich and Tomaka found that anger can lead to different responses in the cardiovascular system. An angering situation is perceived as either a challenge or a threat. 

- Anger with challenge is associated with a stronger response in the heart. There is higher cardiac output (the volume of blood that is pumped out of the heart).

- Anger with threat is associated with a stronger response in the blood vessels. There is higher total peripheral resistance (the amount of constriction of the blood vessels).

- The difference is that in the case of anger with challenge, the person will clearly decide what action to take. With anger with threat, the person’s actions are not that clear.

- Anger with threat differs from anxiety, since in the latter case the action is clear: escape.

- Why the difference between these two types of anger matters so much, is because an ambiguous situation (anger with threat; the action is not clear) prolongs the situation; thus also the physiological response. The anger with threat situation has more crucial health consequences in the long term; because blood vessels are much less efficient regulators of blood circulation that the heart (as you remember, the first is involved in the anger with threat situation).

- Remember that only chronic peripheral resistance leads to persistently high blood pressure; a precursor of cardiovascular diseases.

- Hostility is a known risk factor for cardiovascular diseases. It is described by the tendency to see others as enemies. 

- Hostility is related to the anger with threat response: People are distrustful, suspicious and tend to perceive threat everywhere: Ambiguous situations are interpreted as threatening.

Chapter 3: Persevarative emotional cognition

- After an emotion has long gone, the increased heart rate is often still there.

- The prolongation of an emotion appears to depend only on its negative valence.

- Emotional stressors cause much more lasting responses than physical ones. The reason for this is that the cognitive representation of the stressor continues to be activated for some time. This is called perseverative emotional cognition. 

- Two types of these cognitions are worry (thinking about future threats) and rumination (brooding over the past).

- Worry and rumination cost society a lot of money since people often go to the doctor for it. Worry is presumably also a cause of true somatic illnesses.

- The human brain differs from any other animal. We have a neocortex that is involved in memory and planning. It enables us to think about the past and the future.

- The disadvantage of this is however that we can unlimitedly prolong stressors. The human mind is able to experience stressors chronically.

- An example of this is patient E.P., who had lost his hippocampus do to trauma. He did not have a memory because of this, which resulted in his inability to worry and constant state of happiness.

- Nowadays, the perseverative cognition hypothesis is the idea that our ability to worry can prolong the physiological consequences of these representations of stressors.

- Formerly, the reactivity hypothesis held that frequent and intense cardiovascular responses (e.g. hormonal responses) during stress could lead to the intermediate ‘pathogenic’ states; such as high blood pressure or a dysregulated immune system; leading to disease.

- However, we now know that it is in fact the periods before and after the stressor; in which we worry and ruminate, that end up making us sick.

- Without prolongation, stressors do not increase the risk on somatic diseases.

- Stressors can lead to prolonged activity of the stress response by the interplay of our psychological dispositions (our personality traits and habits how we experience stress). So, perseverative cognitions mediate the effect of stressors on a chronic stress response.

- From another perspective, we can also say that dispositions moderate the effects of stressors on perseverative cognition, hence on prolonged activity and eventually on disease; since we do need triggering events.

- All different types of stressors were found to be related to prolonged increases in cardiovascular activity during sleep.

- The function of sleep is to relax and restore; so stress is not a useful response during this period. The idea we consider is different from bad sleep; sleeping to brief or insomnia.

- A study by Hall et al. showed that the knowledge of having to give a presentation in the morning caused the heart activity and blood pressure of participants to be chronically activated at night. Apparently, we are able to worry unconsciously.

- The majority of studies towards these subjects have shown that when someone regularly feels hostile, anxious, worried and maybe even depressed, their cardiovascular system is continuously activated; both day and night.

- Laboratory research towards worrying often asks participants to worry ‘as they would normally do’. Research towards rumination sometimes manipulates angering situations; and other times people are asked to think of an angering situation of the past. Both show that when people are not distracted from these cognitions, they will experience slower recovery in blood pressure.

- Real-life research showed that daily worrying leads to increased heart activity and elevated levels of cortisol.

- So: stressors, episodes of worrying and having a stress-prone personality seem to lead to prolonged physiological responses. 

- Since the perseverative cognition hypothesis is quite new, there has not been done a lot of research towards the effects of worrying on somatic disease yet.

- However, there are already several studies that have found that worrying leads to an increase in minor physical discomforts; of which for example headaches, neck and back pains and stomach problems are common.

Chapter 4: Unconscious stress

- As mentioned before, stressors and worry appear to be associated with increased 

- We apparently ‘replay’ much of the information of the day unconsciously during sleep. 

- Increased heart rate does not decrease until two hours after worry has already stopped. Maybe unconscious worry is the matter here.

- Prolonged blood pressure increases after experimental anger provocation was found not due to anger-related thought or negative affect. Maybe, unconscious perseverative cognitions are the matter here.

- Studies have showed that showing negative emotional stimuli subliminally can trigger physiological responses; even though the participant is not aware of them.

- When shown subliminally, fear-conditioned pictures cause increased skin conductance; which is directly related to the amount of sweat that is present.

- Subliminally shown negative stereotypes; in the form of words, can trigger an elevation of blood pressure. Positive stereotypes could trigger a decrease in blood pressure.

- Studies have shown that we are not aware of the majority of our cognitions. This might be the same case with stress.

- Research findings suggest that the total load of stress-related physiological activity on an individual is not only dependent upon consciously experienced stressors and perseverative cognitions, but also of unconscious stress-related cognitions.

- Repressive personality types, as described by Sapolsky, have stronger stress responses. Despite their low anxiety they seem to be chronically stressed and have more risk on somatic health diseases.

- Another phenomenon that is related to low emotional awareness is alexithymia; which literally means ‘no words for emotions’. People who have alexithymia carry higher disease risks as well.

- The explanation for this is that emotionally restricted people are not aware of being chronically stressed since they lack awareness of their emotions. Due to their ignorance, these people don’t terminate their stress response, but prolong it.

- Repressive personality types show affective-autonomic dissociation; a discrepancy between their emotional responses and bodily responses. 

- Another theory is that emotionally restricted people may only be aware of their emotions to a limited extent and lack understanding of their bodily stress response. So, they might easily misattribute these subjective somatic complaints to illnesses.