Stress Blunted_vs_Exaggerated Flashcards
```
~~~
Amygdala function? Stress response becomes?
1) Amygdala monitors levels of HSAM and HPAC activation
2) Amygdala can “remember” stimuli associated with heightened stress
* Activation of Type 2 (GR) cortisol receptors —> altered gene expression
* Increased CRF in amygdala —> activates magnocelluar neurons in the PVN
3) Stress response becomes “sensitized” (next time we’re ready for it) and more reactive
* Greater activation of HSAM and HPAC
* Greater activation of CRF feedback system
* Increased attention
* More intense emotional and motivational responses
Outside the Norm Stress Reactivity?
1) Natural variation in stress reactivity
2) Most fall within the “normal” range
3) Some fall outside the normal range:
* Either exaggerated reactivity (hyper-reactivity)
* Or, diminished reactivity (hypo-reactivity)
4) Being outside of the norm (in either direction) more likely to be associated with mental and/or physical health concerns
which stress response? More likely to be associated with?
hyper-reactivity vs hypo-reactivity?
Hyper-reactivity:
1) Exaggerated stress responses
2) More likely to be associated with:
* Cardiovascular disease (high blood pressure, risk of heart attack, risk of stroke)
* Anxiety related stress and disorders, like PTSD
* Anger related traits and disorder (hostility)
Hypo-reactivity:
1) Blunted stress responses
2) More likely to be associated with:
* Obesity and Depression
* Lower IQ and poor executive function
* Alcoholism and addiction
* Risk taking behavior
stress response? negative feedback? which state/behavior?
hyper-reactivity vs hypo-reactivity? May result from?
Hyper-reactivity:
* May result from specific stressful or traumatic experiences (Stress responses “on the look out” for dangers)
* Stress responses, once activated, are difficult to turn off
* Weak negative feedback regulation
* System remains in an elevated states for a prolonged period of time
Hypo-reactivity:
* May result from prolonged early experiences with stress (Stress responses learn to ”not overreact” since stress will be common)
* Stress responses are smaller in magnitude and/or quickly diminished
* Very strong negative feedback regulation
* May result in more impulsive and “sensation seeking” behavior
baseline cortisol and reactivity?
Examples of dysregulated HPA: Anxiety vs. Depression
PTSD
* Lower levels of baseline cortisol (circadian levels)
* Increased cortisol reactivity
Depression
* Higher levels of baseline cortisol
* Decreased cortisol reactivity
Specific traumatic experiences vs Early life stress?
Sensitization and De-Sensitization?
Specific traumatic experiences:
* More likely to sensitize the stress response
* Exaggerated stress reactions
* Poor cardiovascular health (high blood pressure)
* Linked to anxiety and hostility (tend to overreact to situations)
Early life stress:
* More likely to de-sensitize the stress response
* Blunted stress reactions
* Poor behavior regulation and health management (less self-control)
* Linked to risky behavior and sensation seeking (need more stimulation) - More prone to addictive behaviors. Too much alcohol, drugs, food, sex, gambling, etc…
early life stress dysregulation?
1) Many lines of research suggests that early life stress can dysregulate stress responses:
* Most research focuses on dysregulation of the HPA axis
* HPA is the long-term stress response
* Impacts many systems, including the SAM
2) Unclear how exactly early life stress dysregulates the system:
* Different models focus on impact of cumulative stress vs. stress during sensitive periods of development
* No current models precisely predict whether early life stress will lead to hyper- vs. hypo-reactivity
Models of Early Life Stress?
Prolonged and/or chronic stressors “reprogram” the stress response
* Adaptive for environment
* Direction of reactivity (hyper vs. hypo) unclear
Cumulative stress model
* Dysregulation based on total amount of stress experiences in life
Biological Embedding Model
* Dysregulation based on stress during critical periods of development
Sensitization model
* Dysregulation based on the interaction of early life stress with recent stress
* Early life stress “reprograms” but, recent life stress “trigger” the reactivity
Model of Blunted Reactivity?
1) Early life stress reprograms the stress response
2) Blunted reactivity
* Less reaction to stressors
* May enhance approach motivations
* May weaken avoidance motivations
* Poor ability to monitor risk
* Poor ability to inhibit behavior (Lack of self-control)
3) Increased risk of impulsive and self- destructive behaviors
Early Life Stress and Blunted Reactivity?
Extended Early Life Stress appears to be more commonly associated with blunted reactivity:
* Blunted reactivity appears more associated with impulsive behaviors
* Increased risk of alcoholism, addiction, as well as obesity
* Blunted reactivity also associated with depression
* Blunted reactivity also associated with more anti-social behavior
May be adaptive:
* Extended early life stress trains the HPA axis to be less reactive
* System “habituates” to stress. Less cortisol release in response to stress
* Helps avoid the damaging effects of chronically high cortisol levels
Dependent vs Independent variables
Blunted Reactivity Research
Independent variables:
1) Measures of early life stress
* Number of adverse early life events
* Abuse, maltreatment, poverty, etc.
2) Laboratory Stress Test
* Trier Social Stress Test (TSST)
* Social and Math stressors
Dependent variables:
1) Salivary Cortisol (measure of HPA)
2) Heart rate (measures of SAM - sympathetic activation)
3) Personality characteristics
Procedure
Blunted Reactivity Research
1) Participants studied for two days (same time each day)
2) First day involved the Trier Stress Test:
* A 30 minute baseline (read a magazine)
* Then 30 minutes of speech task and 15 minutes of mental math
* Participants do tasks in presence of experimenter in white lab coat
3) Second day was a resting day
* 75 minutes of resting (read magazines, watch a nature video)
baseline cortisol levels? stress reactivity?
Blunted Reactivity Research
No differences in baseline cortisol levels due to early life stress or gender
* On resting days, similar cortisol levels for men and women regardless of early life stress
Early life stress and gender predicted differences in stress reactivity:
* More early life stress —> less reactivity
* Women showed less reactivity
* Less cortisol change.
* Less heart rate change
Personality characteristics
Blunted Reactivity Research
Early Life Stress predicted:
* More antisocial behavior
* More neurotic personality traits (Can be emotionally volatile, irritable)
* More depression symptoms
* More novelty seeking
* Less behavioral control
* Less sociability
Early Life Stress predicted
Blunted Reactivity Research
Early Life Stress predicted:
1) Less executive function
* More difficulty on Stroop Task
2) Less maturity
* Rated to have lower “mental age”
* “Act your age”
3) More impulsivity
* Less able to delay gratification
4) Larger BMI
* More likely to be overweight
