Lecture 17 - Stress - Nov 24th

StressHSCI130 Book Project is 3 days away! HSCI130 Final Exam is 16 days away! Readings Assigned: Cohen et.al. JAMA, 2007 NO OTHER ARTICLE ASSIGNED

Nov 24th, 2009 Lecture Notes Page 1 of 42

foundations of health science

FRIDAYs CLASSBOOK PROJECT DROP OFF BLU11502 between 1pm 4:30 pm *back up copies must be posted on WebCT by 4:30pm *if I have to retrieve your book project via WebCT marks will be deducted. AT 1PM IN CLASS DISCUSSION EXERCISE WILL BE POSTED: ON WEBCT COPIES IN FOLDER ON MY DOOR 5:30 PM ELECTRONIC COPIES OF IN CLASS EXERCISE DUE (if you are not going to use a laptop and will write out answers these are due at 4:30 pm sharp).



Defining StressHow would you define stress? We continuously talk about stress in everyday conversations No universally accepted definition of stress Recognized since Hippocrates disease is pathos + panos; suffering and toil the fight of the body to restore itself Over 10,000 papers on topic since 1967



i-Clicker QuestionHow would you define stress? A) B) C) D) Rate of wear and tear on the body Physical, mental, emotional strain or tension Non-specific response of body to any demand for change Feeling experienced when person perceives that demands exceed personal and social resources



Biological Stress PerspectivesHans Selye Hungarian born Canadian endocrinologist working out of McGill (later University of Montreal) -pioneer of biological effects of stressful stimuli A Syndrome Produced By Diverse Nocuous Agents appears in Nature, 1936Nov 24th, 2009 Lecture Notes Page 5 of 42


Original Description of G.A.S.



General Adaptation SyndromeAlarm-body recognizes a stressor and is in state of alarm -activation of flight-or-fight response + HPA axis

Resistance-follows alarm reaction; removal or disappearance of symptoms -reverse reactions of alarm phase

Exhaustion-bodys resources are depleted and unable to function normally



Biological Stress ResponseSAM System -Walter Cannon early work on fight or flight -increased secretion of epinephrine and norepinephrine -increased blood pressure -increased heart rate -sweating -constriction of blood vessels Consequences: 1. 2. 3. 4. Suppression of cellular immune function Increased blood pressure and heart rate Variations in normal heart rhythms (cause of sudden death) Neurochemical imbalances



Biological Stress ResponseHPA -anterior pituitary gland secretes ACTH -this activates the adrenal cortex to produce cortisol and other glucocorticoids Consequences: At least three pathogenic processes: 1. Cognitive decline 2. Immuno-suppression 3. Insulin resistance



CortisolSaliva, plasma, urinary Saliva = free cortisol Urinary = production & metabolism Diurnal pattern = peaks early and then declines progressively 1. Diurnal slope 2. Size of CAR (cortisol awakening response) 3. Levels of morning and evening cortisolNov 24th, 2009 Lecture Notes Page 10 of 42


">

Dowd, J. B et al. Int. J. Epidemiol. 2009 38:1297-1309; doi:10.1093/ije/dyp277

Nov 24th, 2009 Lecture Notes Page 11 of 42 Copyright restrictions may apply.


Allostatic Load*how does the stress response change over time to facilitate adaptation?Homeostasis=regulation of a limited number of core physiological systems that sustain life (temp, pH); Walter Cannon power to maintain constancy Allostasis = how the organism achieves homeostasis through continual change (survival) Allostatic Load = consequences of sustained activation of primary regulatory systems serving allostasis to burden on bodily systems **cortisol considered one of the primary mediators in range of events**



SES, cortisol & allostatic loadHow does SES get under the skin?

What is the role of chronic stress?Is there evidence that lower SES related to higher levels of cortisol? Is there evidence that lower SES is related to a blunted diurnal pattern? ***NEWSFLASH: LITERATURE REVIEW JUST PUBLISHED!!!***

Dowd, J. B et al. Int. J. Epidemiol. 2009 38:1297-1309; doi:10.1093/ije/dyp277



Findings of Dowd et.al. 2009 Review The notion that chronic stress is an important mediator of the relationship between SES and health outcomes is widespread. Despite the strong intuitive appeal of this hypothesis, current evidence of a consistent relationship between SES and neuroendocrine biomarkers of stress is weak. Better theory and study design should help clarify the expected and observed relationships between SES and HPA-axis activity. pg.1307



Other Perspectives on StressStimulus-stress as probabilistic feature of particular environmental conditions

Response-BasedParticular psychobiological response to differing environmental challenges/stressors (e.g. flight or fight)

Interactive and Dynamic*particulars of organism, the environment and time all key components of concept



Dynamic Perspective Defined Organisms adaptation to challenging environments over time; Successive transactions between the organism and the environment over time (Lazarus & Folkman, 1984)

*external challenges *perceptions of challenges *coping resources *perceptions of coping resources



Contributions from Psychology*psychological processes between environmental events and organisms response-appraisal of environmental stressor -perception of coping resources/mechanisms Perception MAJOR events reduced MINOR events magnified





Measuring Life StressAssess peoples major life events (assumption is life events require varying degrees of readjustment) Schedule of Recent Experiences (first; 1950s): self-report checklists prone to errors Age specific checklists Life Events and Difficulties Scale (Brown & Harris, 1978)

LEDS (gold-standard measure) -interview based -explicit operational criteria or rules for defining evnets -biographical circumstances taken into account when rating life events -differences emerge depending upon the method used



...



...



Problems with Checklists1. Memory and recall of the life event 2. What constitutes a life event; people interpret descriptors in very different ways (e.g.) serious illness or injury 3. Other factors influence how people respond what do participants think the study is about? Background factors? Cultural biases re: stress? People seeking explanations for illness?



1.

a)

Cognitive Appraisal Theory

Lazarus, 1966 i. originated in sociology and psychology ii. developed to describe and explain individual differences in adaptation

Theory: 1. Individuals constantly evaluate their relationship with the environment 2. Behavioural and emotional responses determined by meaning attached to situation/experience 3. Psychological stress occurs when individuals appraise a transaction between themselves and their environment as greater than their resources, thus a threat 4. Three types of stress appraisals (i)harm or loss; (ii)threat or (iii)challenge



CALCULATE YOUR SCORE! Add: #1, 2, 3, 6, 9, 10 = A Reverse Scores: #4, 5, 7, 80=4; 1-3; 2=3; 3=1; 4=0;

Add Reversed Scores = B Perceived Stress Score= A+B



i-Clicker QuestionWhat is your score on the Perceived Stress Scale? A) B) C) D) E) 0 - 9 10 17 18 - 25 26 - 32 33 or higher



Examples



Examples



(from Cohen et.al. 2007)

Stress & CVD

Prospective cohort studies have demonstrated that stress is associated with onset, morbidity and mortality from CVD Work stress (low control+high demands) associated with 50% increase in risk of CVD Risk of CVD also increased among people who have experienced major traumatic events or abuse early in life Stress Prolonged SAM (sympathetic-adrenal-medullary) activation



Stress & Depression(from Cohen et.al. 2007)Evidence from research indicates that stress (measured by life events) is associated with: 1. 2. 3. Onset of major depressive episode Clinical course of major depression Effectiveness of Treatment



Stress & HIV/AIDS(from Cohen et.al. 2007)Evidence from early studies (pre 2000) was inconsistent; argues improvements in measurement may be associated with more conclusive evidence Recent literature links between stress and HIV progression have been documented Influence of stress on other virally initiated illnesses in people with HIV/AIDS



Stress & Cancer

(from Cohen et.al. 2007)

Animal research: stress contributes to initiation, growth and metastasis of tumors Human research: stress affects: antiviral defenses, DNA repair and cellular aging Prospective studies INCONSISTENT with respect to stress and cancer: incidence (perhaps because incidence measuring diagnosis not onset) progression



The Importance of Job Control

Work Stress

The DemNov 24th, 2009 Lecture Notes Page 32 of 42


Base model examining the indirect and direct associations between job control and health status

Smith P M et al. J Epidemiol Community Health 2008;62:54-61

2008 by BMJ Publishing Group Ltd



1.

Sources of stress and coping of high school stuentsa) Mates & Allison (1992) Focus group study of grade 10 students in Toronto (n=23) Students from different streams (basic, general and advanced), ethnic groups, recruited by drug awareness counsellor Results: i. parents and family ii. work and money iii. friends iv. school v. sports vi. gangs and strangers vii. addiction and drugs



1.

a)

Mates & Allison continued..i.Parents:

ii. iii. iv.b)

i.

Work/Money

Well, the parents have some problems of their own and they just take them out on you, like just yell at you If you argue they get mad; if they are arguing with you and you dont say anything, they still get mad You are old enough to know that; youre to young to do that, - well, what are you? -dissatisfaction with boyfriends, strict rules, parental trust, parental opinions about dress If I dont have money, there is nothing to do; unless, like I skateboard, but then you still need money if you are thirsty, you need a drink, or hungry. This whole world revolves around money right now. With money-like its our money, we are making it-theyre saying this is too much for this. It is our money not yours You work and then you come home late event

ii. iii. iv.



1.

Mates & Allison continued..a) Friends:

i. ii.b)

When you get your parents wanting you to go one way, and your friends wanting you to go another, that is really hard. Say you like your girlfriend a lot, and you are talking to her or something, and she is acting negative to you, that makes you mad. You have a time when you dont have any tests, and then you have a time when you have five tests on one day. The teachers really get on your case. You have it from your parents and your teachers. They all give you the same story: Youre capable of doing better work. They treat us like kids too muchThey dont have to patronize us like that.

School

i. ii. iii.

iv.



1.

Mates & Allison continued..a) Coping Responses:

i. Substance Use You smoke to relieve the tension ii. Diversions sports, listening to music, playing an instrument iii. Rebellious Acts doing what you want to do



Stress & Health Among Adolescents..1. mental health: relationship between stress and symptoms of mental illness physical health outcomes lupus, juvenile arthritis health risk attitudes DiClemente et.al. (2001) distressed (*measured by CESD) engaged in more health risk behaviours than non-distressed e.g. unprotected vaginal intercourse, sexual activity with multiple partners

1.

2.



Stress & Health Among Adolescents..4. behaviours: Siqueira et.al. (2000) found following factors associated with smoking: i. negative life events ii. perceived stress iii. frequent use of negative coping methods iv. less use of positive coping methods (problem solving and seeking support)



Adolescent Stress Whos At Risk..1. are particular groups of adolescents at increased risk?: i. adolescents who work? ii. adolescents with chronic diseases? iii. socially disadvantaged adolescents? Goodman et.al. (2005):









Lecture 17 - Stress - Nov 24th

Documents

Transcript of Lecture 17 - Stress - Nov 24th