Stress and IllnessWhat is the Link?

EPI 6181

February 13, 2008

Roxanne Ward

So, what is stress?

Definitions

Stress (Taber’s Medical Dictionary)• The result produced when a structure, system

is acted upon by a stressor. Generally believed that biological organisms require a certain amount of stress in order to maintain their well-being

Stress (Hans Selye)•Mechanism – the non-specific response of the body to any demand•Can be good (eustress) or bad (distress)

Stress (Wolf - 1953)• Man’s response to many sorts of noxious agents

and threats, including “meaning” for individual •Interaction between organism and environment; dynamic

Strain (Dictionary)

• To injure by making too strong an effort or excessive use

Physiology of Stress

• Nervous System– Central– Peripheral

• Autonomic – Sympathetic

– Parasympathetic

• Endocrine System– Hypothalamic-pituitary-adrenal (HPA) axis– Sympathetic Adrenal Medulla (SAM) response

Autonomic Nervous System

Endocrine System• Sympathetic Adrenal Medulla Response

Hypothalamus

Sympathetic NS

Adrenal Medulla

Epinephrine & Norepinephrine

HR, BP, RR, BS

Endocrine SystemHPA axis

Hypothalamus

ACTH

Adrenal Cortex

Glucocorticoids & Mineralcorticoids

Protein & Fat Metabolism, BP &

Blood volume

Inflammatory Response

The Pioneers – Their Contributions

• Cannon – Physiologist (1920’s)– Homeostasis

• A condition which may vary but which is relatively constant

– Fight or Flight Response (basic survival instinct)• Fundamental physiologic response to body’s perceived

threat to survival

The Pioneers – Their Contributions

• Hans Selye (1956)– The General Adaptation Syndrome

• Different diseases seem to cause similar symptoms = general response

• Operates in response to longer term exposure to stress

General Adaptation Syndrome

SAM activated

HPA activated

Problems with Response- Based Views

• Unable to explain different responses in different individuals

• Don’t consider the effect of individual’s perception on the stress response

• Circularity of theory

Other Important Contributors

• Martin Seligman– Learned Helplessness (1967)

• Related to lack of control

• Richard Lazarus– Cognitive Motivational Relational Theory of

Emotion (1986)• Response to stress affected by individual’s thoughts &

perceptions – relational phenomenon between individual and environment

• Takes into account individual differences in motivational and cognitive variables

• Well-known for work on coping

• Cox (1978)– Stress as a perceptual phenomenon

Demand

Stress Responses

Cognitive/Behavioral Response

ReappraisalPerception

Problems With Model

• How do we account for perceptions of all individuals?

• We often respond to stress/demands without conscious evaluation

How To Measure Stress?• Three methods to assess role of stress in

disease risk:– Environmental – what are the objective conditions

that promote stress & lead to disease (stimulus based)

– Psychological – based on individual’s interpretation of the meaning of the event and ability to cope Based solely on individual’s perception

– Biological – activation of physiologic systems affected by psychological & physically demanding conditions (Stress hormones, cardiovascular response, immune measures)

Environmental Perspective

• Checklist

– Social Readjustment Rating Scale (SRRS) (Holmes & Rahe 1967)

• Includes both positive & negative events

• Some items could be viewed as symptoms or consequences of illness

– Interview Measurement

• Allows probing; beneficial when looking at relationship of timing between event and response

• Expensive, requires special training

Environmental Perspective (2)

• Daily & Within Day Event Measures• Assess impact of daily events on physical & mental health

– Daily Life Experience (DLE) Checklist

– Hassles Scale

• Problems with circularity and confounding – some items on scale resemble psychological symptoms

• Measurement of Chronic Stressors– Makes sense to link chronic stress to diseases that

develop over a period of time• Self Report, Observational, Interviews

– Life Events & Difficulty Schedule (LEDS)

– Mult-measure may control for measurement error

Psychological Perspective

• Measurement of stress appraisal– Single-item questions; Self-report scales;

Interview-based• How to differentiate appraisal from other

psychological processes?

• Measurement of affective response– Most common method – Adjective

Checklists– Observational methods

Biological Perspective

• Measurement of Stress Hormones– Epinephrine, norepinephrine;

corticosteriods: cortisol, serotonin

• Measurement of Cardiovascular Responses– Role in maintaining homeostasis

– Blood Pressure, Heart rate, ECG

• Measures of Immune Response

Stress & Illness

Stress linked to:• Cardiovascular Disease• Gastric Ulcers• Hypertension• Viral illness• Cancer?• Anxiety• Depression

Stress: The Illness Connection

• Link between breast cancer & stress?• Potential relation between stress and risk of breast

cancer – different study designs, conflicting results• Risk of breast cancer and acute stress of major life

events, but less attention to effect of perceived “daily stress”

• 2005 – Self Reported stress & risk of breast cancer: prospective cohort study

– Reduced risk of breast cancer

• 2004 – Job stress & breast cancer risk– Job stress not related to increase in breast cancer risk

Social Stress

• Origins– Individual experiences of ongoing strains &

negative events within social roles are products of social stratification by gender, race, social class

• Outcome of social organization – systematic discrimination & inequity

• Are members of lower class groups physically more vulnerable to effects of stressors?

Social Status & Illness: Is Stress the Path Between?

• Summary of literature (Thoits)– Experience of negative major life events & chronic

difficulties risk of psych problems & physical illness

– Sense of personal control over life circumstances psych symptoms & acts as buffer

– Social integration probability of morbidity & mortality

– Perceived emotional support psych symptoms & acts as buffer to neg. events & chronic strains

Research

• 2008 – The influence of active coping & perceived stress on health disparities in a multi-ethnic low income sample– Higher perceived stress related to poorer

general health for all ethno-racial groups– Perceived stress critical component in

understanding health outcomes

Research

• 2007 – Subjective social status (SSS), objective SES & cardiovascular risk in women– Women with SSS had more

cardiovascular risk behaviors– Evidence that perception of one’s social

status could have important health implications beyond objective SES

References• Cohen S, Kessler RC, Gordon LU. Measuring stress. New York: Oxford University

Press, 1995. • Thoits PA. Stress, coping, and social support processes: where are we? What next?

J Health Soc Behav 1995;36(Suppl):53.• Lazarus RS, From psychological stress to the emotions: A history of changing

outlooks. Annu Rev Psychol 1993;44:1-21.• Cassel J. Psychosocial processes and “stress”: theoretical formulation. Int J Health

Serv 1974;4:471:82• Dohrenwend BP, Shrout P. “Hassles” in the conceptualization and measurement of life

stress variables. Am Psychol 1985;40:780-785.• Theorell T, Karasek RA. Current issues relation to psychosocial job strain and

cardiovascular disease research. J Occup Health Psychol 1996;1:9-26.• Cooper CL, Faragher EB. Psychosocial stress and breast cancer. In: Plotnikoff N, ed.

Stress and immunity. Boca Raton: CRC Press Inc, 1991:259-282.• Watson J, Logan H, Tomar SL. The influence of active coping and perceived stress on

health disparities in a multi-ethnic low income sample. BMC Public Health 2008; 8: 41.• Schernhammer E, Hankinson S. Job stress and breast cancer risk; The nurses’ health

study. Am J Epi 2004;160:1079-1086.• Ghaed SG, Gallo LC. Subjective social status, objective socioeconomic status and

cardiovascular risk in women. Health Psychol 2007;26(6):668-674.