Ch05: Stress — GAS, Appraisal & Health Effects（应激）

Preparatory Mindset

Stress is the most-examined topic in medical psychology after development. The lecture (14 Stress, 13.9KB) covers definition, GAS (General Adaptation Syndrome), fight-or-flight, primary/secondary appraisal, psychoneuroimmunology, and stress management. The review docx adds the types of stressors and stress-related disease.

Exam mindset: know Selye's GAS (3 stages: alarm → resistance → exhaustion), Lazarus's primary vs secondary appraisal, the fight-or-flight response (acute stress), and allostatic load (chronic stress).

Core Concepts

1. Definition of stress (MUST KNOW)

• Stress: a negative emotional state occurring in response to events that are perceived as threatening or challenging
• Stressor: events or conditions that trigger the stress response because they are perceived as overwhelmingly challenging and threatening
• Stress is the nonspecific response of the body to any stressor (Selye) — any stimulus that activates the HPA axis

2. Types of stressors

• Physical: pain, infection, trauma, cold, heat, noise
• Psychological: life changes (death, divorce, job loss), daily hassles, work stress, interpersonal conflicts, exam stress
• Social: poverty, discrimination, social isolation, lack of support
• Acute (time-limited) vs. chronic (persistent) — chronic stress is the disease precursor

3. Fight-or-Flight response (Cannon) (MUST KNOW)

• Acute stress response: automatic reaction to a threatening or potentially dangerous situation
• Triggered by the release of hormones (catecholamines: epinephrine, norepinephrine) that prepare the body to fight or run
• Adaptive — enables the organism to respond quickly to threat
• Harmful when prolonged — disrupts emotional and physiological functioning; can cause medical problems over time

4. General Adaptation Syndrome (GAS) — Selye (MUST KNOW)

1. Alarm (fight-or-flight): sympathetic activation, catecholamines, cortisol release; glucose mobilization, increased HR/BP, pupil dilation, bronchodilation 2. Resistance (adaptation): body tries to adapt; cortisol remains elevated; gluconeogenesis; immune function initially maintained then suppressed 3. Exhaustion (depletion): prolonged stress depletes adaptive resources; HPA axis dysregulation; impaired immunity, illness, organ damage, death

• Describes the physiological changes the body goes through when under stress
• Three stages:

5. Stress appraisal — Lazarus (MUST KNOW)

• Primary appraisal: evaluation of a situation to determine whether it poses a threat or not — analysis of harmfulness, benefit, or irrelevance of a potential threat
• Secondary appraisal: analysis of available resources and whether they will assist in overcoming a threat — depends on personality profile, coping skills, social support
• If both → cope; if threat >> resources → stress response
• Reappraisal: ongoing re-evaluation; may change the initial assessment

6. Physiological response (MUST KNOW)

• HPA axis: hypothalamus → CRH → anterior pituitary → ACTH → adrenal cortex → cortisol (chronic stress)
• LC-NE system: locus coeruleus → norepinephrine (acute arousal)
• SAM axis: sympathetic adrenal medullary — epinephrine/norepinephrine (seconds)
• Endocrine also: GH, prolactin, vasopressin; reproductive suppression

7. Cognitive effects (MUST KNOW)

• Memory: enhanced consolidation of emotional memories; impaired working memory under high stress
• Attention: narrowed to threat (attentional bias)
• Decision-making: risk-averse (prefrontal cortex suppressed by amygdala)

8. Stress-related disease (MUST KNOW)

• Cardiovascular: hypertension, MI, stroke
• Immune: ↓ immune function, infections, autoimmune flare, cancer progression
• GI: peptic ulcer, IBS, IBD
• Mental: anxiety, depression, PTSD, burnout
• Metabolic: diabetes, metabolic syndrome
• Reproductive: infertility, menstrual irregularities

9. Psychoneuroimmunology (PNI)

• The study of interactions between psychology, nervous system, and immune system
• Stress → cortisol → immunomodulation → ↑ infection risk, ↓ vaccine response, ↑ tumor progression
• Behavioral immunity: motivation to avoid sick others (influenced by disgust, cytokines — sickness behavior)

10. Allostatic load

• The cumulative wear and tear on the body from chronic stress (vs. short-term homeostasis)
• Mediators: cortisol, catecholamines, inflammatory cytokines
• High allostatic load → accelerates aging, atherosclerosis, diabetes, depression

11. Stress management

• Behavioral: exercise (the most consistent), sleep, nutrition, social support
• Cognitive: cognitive restructuring, mindfulness, meditation, relaxation training, biofeedback
• Social: social support, problem-solving, time management
• Clinical: CBT (most evidence-based), stress inoculation, mindfulness-based stress reduction (MBSR)

High-Yield Points

• Stress = negative emotional state from perceived threats (Selye: nonspecific response to any stressor)
• Fight-or-flight: acute catecholamines (Cannon)
• GAS (Selye): 3 stages — Alarm → Resistance → Exhaustion
• Primary appraisal: threat? Secondary appraisal: resources to cope?
• HPA axis: CRH → ACTH → cortisol (chronic stress hormone)
• Chronic stress → ↓ immune function, hypertension, depression, GI disease
• Allostatic load = cumulative wear; accelerates aging
• Exercise = best single stress-management tool
• CBT = most evidence-based therapy for stress
• Mindfulness/MBSR for stress & anxiety

Topic Summary

Stress is a negative emotional state from perceived threats; the stressor is the triggering event. The fight-or-flight response (Cannon) is the acute adaptive reaction mediated by catecholamines. Selye's General Adaptation Syndrome (GAS) describes 3 stages: alarm (catecholamine surge), resistance (cortisol-mediated adaptation), exhaustion (resource depletion → disease). Lazarus's cognitive appraisal model distinguishes primary (threat assessment) and secondary (resource assessment) — the appraisal process determines the stress response. The HPA axis (CRH → ACTH → cortisol) and the SAM axis govern the physiological response. Chronic stress causes cardiovascular disease, immune suppression, GI disorders, depression/PTSD, and metabolic disease. Allostatic load is the cumulative wear-and-tear from chronic stress, accelerating aging. Treatment includes exercise, CBT, mindfulness/MBSR, social support, and stress-management skills.