1 Psychology and human development1.9 Emotion
1.9.4 Stress
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Written by Resident Doctor Committee · Published
Stress and arousal
Stress arises when a person judges that demands exceed their resources; Selye called the demand the stressor.
The Yerkes-Dodson law is an inverted-U relationship between arousal and performance: performance is best at moderate arousal and poorer at both low and high arousal.
The optimum arousal is lower for complex tasks.
Cognitive appraisal
Lazarus's cognitive appraisal theory holds that distress follows from how a person appraises a demand against the coping resources they believe they have, not from the event itself.
This explains why an identical stressor produces different outcomes in different people.
Lazarus and Folkman's transactional model has two stages of appraisal.
Appraisal | Question it answers | Judgements |
|---|---|---|
Primary | What does this encounter mean for my well-being? | Harm-loss (damage done), threat (harm anticipated) or challenge (difficult but an opportunity) |
Secondary | What can I do about it? | Coping options, control, support and experience |
Reappraisal updates both judgements as coping succeeds or fails, so cognitive treatment can change the response without changing the event.
Physiological response
Feature | Sympathetic-adrenomedullary system | Hypothalamic-pituitary-adrenal (HPA) axis |
|---|---|---|
Pathway | Sympathetic fibres and the adrenal medulla | Corticotrophin-releasing hormone, then adrenocorticotrophic hormone, then cortisol from the adrenal cortex |
Speed | Seconds to minutes | Cortisol peaks 20 to 30 minutes after onset |
Mediators | Adrenaline and noradrenaline | Cortisol, which feeds back to end the response |
Selye's general adaptation syndrome has three stages: alarm, resistance and exhaustion.
Allostatic load is the cumulative cost of repeated activation, such as hypertension, insulin resistance and suppressed immunity.
Measuring life events
Social Readjustment Rating Scale
Holmes and Rahe's Social Readjustment Rating Scale (1967) weights 43 life events in life change units, with marriage as the anchor at 50.
Event | Life change units |
|---|---|
Death of a spouse | 100 |
Divorce | 73 |
Marital separation | 65 |
Jail term | 65 |
Death of a close family member | 63 |
Personal injury or illness | 53 |
Marriage | 50 |
Annual totals were associated with later illness.
Every event carries a fixed weight, so the scale scores occurrence, including desirable events, and ignores the personal meaning and appraisal of the event.
Life Events and Difficulties Schedule
The Life Events and Difficulties Schedule is an investigator-based interview in which trained raters, not respondents, judge the contextual threat an event would carry for a typical person in the same circumstances.
Raters set aside the respondent's own reaction, which reduces contamination by current mood.
Event type | Definition | Example |
|---|---|---|
Independent | External, and could not have been brought about by the person's behaviour, personality or emerging illness | Redundancy through a whole-site factory closure |
Dependent | Partly generated by the person or the developing illness | Dismissal, relationship breakdown |
Entrapment is a category of severe event that confirms the person is stuck in a long-standing marked difficulty with no realistic way out.
Depression follows loss combined with humiliation or entrapment most closely.
Chronic difficulties add to the impact of events; prolonged infertility affects the individual (guilt, lowered self-esteem, low mood), sexual life (reduced frequency and spontaneity) and the relationship (more conflict) together.
Life events and depression
Brown and Harris's Camberwell community study of 458 women, The Social Origins of Depression, linked provoking agents and vulnerability factors to the onset of depression.
Factor | Role | Examples |
|---|---|---|
Provoking agent | Determines whether an episode starts | Severe life event, major long-term difficulty |
Vulnerability factor | Raises risk only when a provoking agent is present | The four listed below |
Symptom formation factor | Shapes severity and form once the episode begins | Earlier loss |
The four vulnerability factors are:
The woman has three or more children under 14 at home.
The woman has no employment outside the home.
The woman lost her mother before age 11.
The woman has no confiding relationship, and this factor had the strongest effect.
A severe life event is a provoking agent, not a vulnerability factor.
Entrance events, which are desirable, occur at similar rates in depressed patients and controls, so a lack of positive events is not an established cause of onset.
Vulnerability and gene-environment interaction
The diathesis-stress model holds that a disorder arises when an underlying predisposition meets a precipitating stressor, and that neither is sufficient alone.
5-HTTLPR, a promoter polymorphism in the serotonin transporter gene (SLC6A4), was reported to moderate the risk of depression after stressful life events, the classic gene-environment interaction.
Replication of the 5-HTTLPR finding has been inconsistent.
Learned helplessness
Seligman and Maier gave dogs inescapable shocks; the dogs later failed to escape when escape became possible, while dogs previously able to escape learned readily.
Uncontrollability, not the shock itself, produced the passivity, and learned helplessness was proposed as an aetiological model of depression.
Type A behaviour
Friedman and Rosenman's Type A behaviour pattern is hard-driving competitiveness with chronic time urgency, proposed and first supported prospectively as a risk factor for coronary heart disease.
Type B describes a relaxed, unhurried pattern.
Later replication was inconsistent, and hostility carried more of the predictive association.
Neurasthenia
George Miller Beard introduced neurasthenia for a syndrome of nervous exhaustion attributed to the strain of modern life.
Weir Mitchell did not coin the term; he only treated the condition, with the rest cure.