stress and illness what is the link? epi 6181 february 13, 2008 roxanne ward
TRANSCRIPT
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.