Post on 13-May-2015
Stress Across Life: Biological Correlates
Biological Correlates of Stress among Adults
Prof. Hani Hamed Dessoki, M.D.Psychiatry
Prof. Psychiatry
Chairman of Psychiatry Department
Beni Suef University
Supervisor of Psychiatry Department
El-Fayoum University
APA member
Biological Psychology
Stress
HISTORYHISTORY
Selye (1937) pioneered the field “Stress research”
Nonspecific, stereotypic responses to adverse conditions.
General adaptation syndrome.
Christian (1950s)Christian (1950s)
Relationship between stressors & population density.
Association between increased population density and activation of the pituitary-adrenal axis .
Since then, growing awareness of influence of stress on physiology and behavior.
Stress is an enescapable factStress is an enescapable fact of lifeof life
What is STRESS ?
Stress is a state resulting from events (stimuli) of external or internal origin, real or imagined that tend to affect the homeostatic state.
Stress and Health
Overview of Terminology
Stress: A state of disharmony or a threat to homeostasis
Physiological changes increase alertness, focus, and energy
Perceived demands may exceed the perceived resources
Coping: The ability to maintain control, think rationally, and problem solve
Resilience: Resistant quality that permits a person to recovery quickly and thrive in spite of adversity
Stress
EustressManageable Stress can lead to growth and enhanced competence
DistressUncontrollable, prolonged, or overwhelming stress is destructive.
Acute StressImmediate response to a threat or challenge
Chronic StressOngoing exposure to stress, may seem unrelenting
PhysicalPhysical
Events having direct physical threat.
Cold, heat,infection,
toxic substance, etc.
Psychological
Failure to achive goals.
Dath of loved ones,Job demands,interpersonal problems,financial problems, etc.
Stressful situation Psychological Stress
Sub-Types
Social : Financial problems, dominance , hierarchy insult, loss of self esteem.
Occupational : Work place problems, insufficient pay, uneasy relationship with coworkers.
Life stressors: Parking place problems, running late, dealing Spouse/children, divorce, isolation.
Philosophical/Spiritual : Meaning and purpose of life, belief in higher power, loss of values.
Physical and Psychological stressors are often intertwined.
© 2012 John Wiley & Sons, Inc. All rights reserved.
Seven Major Sources of Stress
STRESS RESPONSE
GASTROINTESTINAL
METABOLIC
CARDIOVASCULAR
REPRODUCTIVE GROWTH AND REPAIR
IMMUNE
Digestion is inhibited (Enzyme action inhibited)
STRESS RESPONSE
METABOLIC CARDIOVASCULAR GASTRO INTESTINAL GROWTH & REPAIR IMMUNE REPRODUCTIVE
Increased heart rate and blood pressure to speed delivery of glucose and oxygen to tissues that need it
Digestion is inhibited (Enzyme action inhibited)
Inhibition of growth hormone and other anabolic processes
Depletion of lymphocytes (suppression of immune response)
Inhibition of reproductive functions
Triglycerides, glycogen and proteins are degraded and converted in to carbohydrates to provide immediate energy.
How these changes are induced ?How these changes are induced ?
CNS : Activation of Sympathetic nervous system, catecholamines excite cells/tissues. (Sympatho-adrenal system)
Endocrine: CRH, ACTH, Glucocorticoids, Adrenalin, vassopressin, endorphins.
Stress
Brain areas
Preganglionic
Fibers
Adrenal Medulla
Adrenalin
PVN
CRH/AVP
Pituitary
ACTH
Adrenal cortex
Glucocorticoids
Peripheral sites
B-endorphin
Behavior
What is the role of -endorphin?
A natural pain killer.
Inhibits synaptic transmission to prevent pain perception.
In the absence of -endorphin stress response exaggerated.
Stages of the Stress ResponseGeneral Adaptation Syndrome of Hans Selye (1907-1982)
Alarm—when one feels threatenedActivation of the fight or flight reaction
Resistance—mobilization of resources to solve the problem
Continued stress causes adaptation
ExhaustionAdaptation fails and level of function decreases
Models for Understanding StressThe General Adaptation Model
Allostasis
Maintaining stress and adaptive responses over the long term implies high levels of activation of the homeostatic processes
This causes wear and tear, called 'allostatic load'.See Selye's General Adaptation Syndrome diagram showing the level of endocrine response mounted:
Resting responselevel
Stress Paradox
ExhaustionBody is at depleted state
Must rest in order to recover
If stress continues without recovery or exhaustion =illness
perpetuation of illness
death
Stress and the Immune System
Psychoneuroimmunology
Interdisciplinary field that studies the effects of psychological and other factors on the immune system
The biological response to stress changes the activity of the immune system, increasing the risk of:Cancer
Periodontal Disease
Common Cold
Bursitis
Colitis
Rheumatoid Arthritis
Alzheimer’s
© 2012 John Wiley & Sons, Inc. All rights reserved.
Stress and Cognitive Functioning
Cortisol Effects on the Brain
SHORT TERM: Cortisol also can prevent the retrieval of existing memories, as well as the laying down of new memories
LONG TERM: Prolonged stress can permanently damage the hippocampus, a key part of the brain involved in memory. Once damaged, it cannot provide proper feedback to the hypothalamus, so cortisol continues to be secreted and a vicious cycle can develop
© 2012 John Wiley & Sons, Inc. All rights reserved.
Stahl S M, Essential Psychopharmacology (2000)
BDNF gene
StressStress
Stress
BDNF
Stahl S M, Essential Psychopharmacology (2000)
Apoptosis
Coping With Stress
Direct copingIntentional efforts to change an uncomfortable situation
ConfrontationAcknowledging stress directly and initiating a solution
CompromiseChoosing a more realistic goal when an ideal goal cannot be met
WithdrawalAvoiding a situation when other options are not practical
Notional model of emotions that arise fromthe balance between level of challenge and a person’s coping ability
Confidence
Challenge
apathyboredom
relaxation
control
engagement,flow
arousal
apprehension,anxiety
worry
high
highlowlow
The Role of Epigenetic Modulationin Major Depression and Schizophrenia
Champagne et al. 2005; Copyright Elsevier (2005).
Externalenvironment
Maternal careMaternal care Social experiencesSocial experiences
Geneticbackground
Geneticbackground
EARLY EXPERIENCESEpigenetic modifications 1
AdultFertilization Pre-natal Postpartum Post-weaning
REVERSIBILITYEpigenetic modifications 2
Behavioralphenotype
Stress and Ageing
Psychological stress is linked to oxidative damage of DNA and other cellular components Experimental Evidence
Study of Blackburn & her colleagues
Selected 58, normal, healthy mothers
19 Controls : Problem free children
39 Stress group: Chronically ill child
Blood samples were drawn and 3 parameters of cellular ageing analyzed:
1. Telomere length : Women with perceived stress had shorter
telomeres, extent of shortening was equal to
10 years of additional aging
2. Telomerase activity :
About 50% less in stressed women
3. Oxidative stress : Higher in stressed women
A telomere
A telomere is a region of repetitive nucleotide sequences at each end of a chromatid, which protects the end of the chromosome from deterioration or from fusion with neighboring chromosomes. Its name is derived from the Greek nouns telos (τέλος) 'end' and merοs (μέρος, root: μερ-) 'part.' Telomere regions deter the degradation of genes near the ends of chromosomes by allowing chromosome ends to shorten, which necessarily occurs during chromosome replication.Without telomeres, the genomes would progressively lose information and be truncated after cell division because the synthesis of Okazaki fragments requires RNA primers attaching ahead on the lagging strand. Over time, due to each cell division, the telomere ends become shorter.
Telomeres
.
The study showed only an association between depression and shorter telomeres, and didn't prove a cause-and-effect link. The researchers said they aren't entirely sure what the shorter telomeres might mean in depression.
On one hand, study author Josine Verhoeven said, it could be that having shorter telomeres somehow sets a person up for mental troubles. But it's more likely that depression causes damage that leaves traces even at the cellular level, she said.
Depression is known to disrupt many physical systems. It alters hormones, suppresses the immune function and changes how nerves work. People with a history of depression have greater risks for diseases of aging, such as heart disease, type 2 diabetes, dementia and cancer.
"Results like ours suggest that psychological distress, as experienced by depressed persons, has a large, detrimental impact on the wear and tear of a person's body, resulting in accelerated biological aging," said Verhoeven, a doctoral researcher at VU University Medical Center in Amsterdam.
study was published online Nov. 12 in the journal Molecular Psychiatry.
One expert said the study is significant in the number of people it involved.
"The strength of this report is its size," said Etienne Sibille, an associate professor of psychiatry at the University of Pittsburgh. He is studying how depression ages the brain.
Sibille said previous research on the same question had mixed results -- probably because the studies were too limited to pick up the effect, which is small and varies from person to person.
"It's a small effect, but it's real," he said.
The next question science needs to answer, Sibille said, is whether telomere shortening really matters and if reversing it could improve health. Other studies have shown that a healthier diet, exercise and measures to control stress may lengthen telomeres.
"It's just not known whether it has an impact on cell function," he said. "If that's the case, it has potential therapeutic importance."
More information
Head to the U.S. Centers for Disease Control and Prevention for more on healthy aging.
SOURCES: Josine Verhoeven, doctoral researcher, VU University Medical Center, Amsterdam, Netherlands; Etienne Sibille, Ph.D., associate professor, department of psychiatry, University of Pittsburgh; Nov. 12, 2013, Molecular Psychiatry, online
Measuring YOUR Life Changes!
© 2012 John Wiley & Sons, Inc. All rights reserved.
Stress ManagementStress Management
1. Proper diet, exercise & relaxation.
Avoid hurry, Worry & curry.
2. Yoga: Flexing & bending of body parts along with controlled breathing does not cause fatigue like aerobic exercise.
3. Pranayama: Regulated deep breathing, rich
oxygen supply - relieves of stress.
4. Meditation: Relaxation of body & mind : reduces
excitation.
5. Accept reality, accept you can not change.
6. Avoid personal confrontation.
7. Humor: Takes sting out of stress.
8.Laughter: Physical & emotional effects :
Muscular activity burns calories,
reduces stress hormone levels,
increases endorphins, boosts
immunity.
9. Music : Soothing effect.
10. Sports, Games, Hobby.
Summary
"Stress reactivity is better understood as the result of intertwined biological and psychological processes that ultimately ensure an organism's survival.“
"There is a cost to frequent physiological adjustments (allostatic load)“
“One of the most interesting findings emerging from the research ... is that in the absence of supportive care, stressors experienced during sensitive periods of development can ... leave permanent imprints in the neural substrate of emotional and cognitive processes. ... the nervous system of mammals carries their singular epigenetic history and expresses it in unique but predictable ways”.