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Stress and Memory: 2. Dr. Sarah N. Garfinkel Brighton and Sussex Medical School. Applied Cognitive Psychology. Post Traumatic Stress Disorder (PTSD). Vietnam veteran with PTSD related the following memory:. .

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Stress and memory 2

Stress and Memory: 2

Dr. Sarah N. Garfinkel

Brighton and Sussex Medical School

Applied Cognitive Psychology



Stress and memory 2

Vietnam veteran with PTSD related the following memory:

.

Iwas a body bagger (responsible for picking up dead bodies). We were going out in a chopper, picking up bodies. We had overlooked a marine who had been killed. By the time we went out to get him he had been dead for a week. I went to pick him up, and my arm went right through him. I was standing there, holding his heart, guts, and insides in my hand

Bremner and Brett, 1997


Ptsd symptom clusters
PTSD: Symptom Clusters

• Intrusion—memories of the trauma or “flashbacks” that occur unexpectedly; these may include nightmares or physical reactions such as a racing heart

• Avoidance—avoiding people, places, thoughts, or activities that bring back memories of the trauma; this may involve feeling numb or emotionless, withdrawing from family and friends, or “self-medicating” by abusing alcohol or other drugs

• Hyperarousal—feeling “on guard” or irritable, having sleep problems, having difficulty concentrating, feeling overly alert and being easily startled, having sudden outbursts of anger


Ptsd prevalence
PTSD prevalence

  • Statistics regarding this illness indicate that approximately 7%-8% of people in the United States will likely develop PTSD in their lifetime, with the lifetime prevalence in combat veterans and rape victims ranging from 10% to as high as 30%.

  • Institute of Psychiatry in London: “Studies of at-risk groups e.g. combat veterans, victims of natural disasters or criminal violence have yielded prevalence rates ranging form 3% to 58%”.


Outline
Outline

  • Memory for the original trauma

    • Stability over time?

    • Relationship between memory change and PTSD symptoms

  • Is a lack of memory for the trauma protective?

  • Treat or prevent PTSD by interventions that specifically target memory?

  • Altered neurocircuitry in PTSD

    • Predisposing factor vs. acquired sign?

    • Can this altered neurocircuitry contribute to the maintenance of fear memories?


Memory and ptsd
Memory and PTSD

  • The person experienced, witnessed, or was confronted with an event or events that involved actual or threatened death or serious injury, or a threat to the physical integrity of self

  • The person’s response involved intense fear, helplessness or horror

Assessed retrospectively: Memory for the trauma & memory for acute response to trauma


Memory for traumatic events
Memory for traumatic events

  • Stable and indelible vs. subject to alteration and distortion?

“Indelible” conditioned fear responses (LeDoux, 1996; McGaugh 2003; Pitman 1989)

Reconsolidation (Nader, Schafe, LeDoux 2000a; Schiller, Monfils, Raio, Johnson, LeDoux, Phelps 2010)


Stress and memory 2

Severity of Trauma

PTSD

Interaction with vulnerability factors [genetics, childhood abuse, etc]

Trauma

PTSD

Interaction with vulnerability factors [genetics, childhood abuse, etc]

Perceived severityof Trauma


Memory amplification and ptsd world trade center
Memory amplification and PTSD: World Trade Center

  • 2641 disaster restoration workers during or after 9/11.

  • T1 & T2 [1 year later].

  • [CAPS]: re-experiencing, avoidance/numbing & hyperarousal.

  • WTC Exposure Questionnaire: 11 exposure variables examined:

  • Memory change score: Number of exposure variables endorsed T2 – Number exposed T1


Stress and memory 2

Traumatic endorsements between T1 and T2

Percentage of people

Amplification of memory for two specific items (‘seeing bodies’ & ‘perceived life threat’) was associated with CAPS increase over time.


Stress and memory 2

Tsunami

Increased recall of threat intensity associated with increase in / lack of improvement in IES-R symptom score

PTSD symptomatology

Heir et al., 2009

Memory amplification


Nature of traumatic memory
Nature of Traumatic Memory

  • Traumatic memory does not remain stable over time

  • Increase in propensity to endorse traumatic items predicts PTSD

  • Memory amplification: Unclear whether this is increasing or decreasing in accuracy


Does amnesia for the traumatic event play a protective role
Does amnesia for the traumatic event play a protective role?

  • Traumatic events involving traumatic brain injury are associated with reduced prevalence of PTSD > Amnesia of the traumatic event may play a protective role (Mayou et al., 1993; Sbordone & Liter, 1995)

  • TBI and PTSD not mutually exclusive (Bryant & Harvey, 1998; Ohry et al., 1996).

  • >> These studies lack systematic investigation of memory for the event


Stress and memory 2

120 subjects injured primarily in traffic accidents (90%).

Initial evaluation took place within 24 hours after injury, during hospitalization. Also, follow up 7-10 days, 4 weeks and 6 months.


Stress and memory 2

55% explicit memory of the traumatic event and subsequent development of PTSD in participants who had experienced TBI

45%

23% met diagnostic criteria for PTSD at 6 months

*

6% met diagnostic criteria for PTSD at 6 months


Stress and memory 2

Question… explicit memory of the traumatic event and subsequent development of PTSD in participants who had experienced TBI

If lack of memory for the traumatic event is “protective”, can:

a) the memory be weakened and b) is a weakened memory protective against subsequent PTSD development?


Interfering with the trauma memory
Interfering with the trauma memory explicit memory of the traumatic event and subsequent development of PTSD in participants who had experienced TBI

  • Increased epinephrine is thought to mediate enhanced memory for emotional events

Excess

epinephrine

Trauma

PTSD symptoms

Strong emotional

memory and

fear conditioning

Young & Breslau, 2004

  • Searing in of memory adrenergically mediated → Blocking (e.g. β – adrenergic blocker propranolol) interferes with memory formation.


Stress and memory 2

CAPS Score explicit memory of the traumatic event and subsequent development of PTSD in participants who had experienced TBI

Propranolol Placebo

One-Month

Propranolol Placebo

Three-Month

Pitman et al., (2002)


Stress and memory 2

Skin Conductance explicit memory of the traumatic event and subsequent development of PTSD in participants who had experienced TBI

Physiologic responses during personal script-driven imagery of the traumatic event that occurred 3 months earlier

SC (sd)

t=2.0, p=.03

Placebo Propranolol

Findings not replicated (Stein et al., 2007). Administration time? 48 hours max vs. 1-6 used by Pitman


Interim summary
Interim Summary explicit memory of the traumatic event and subsequent development of PTSD in participants who had experienced TBI

  • Memory amplification over time is associated with PTSD symptoms

  • Blocking memory for the original trauma has a “protective” effect against getting PTSD

    • Amnesia following TBI

    • Drugs following trauma (impair memory consolidation)


Stress and memory 2

Question… explicit memory of the traumatic event and subsequent development of PTSD in participants who had experienced TBI

Does the trauma memory activate different parts of the brain in PTSD patients?


Symptom provocation studies
Symptom provocation studies explicit memory of the traumatic event and subsequent development of PTSD in participants who had experienced TBI

Show traumatic reminders to patients with PTSD, and investigate whether different patterns of brain activity are observed.


Hyperactive amygdala
Hyperactive explicit memory of the traumatic event and subsequent development of PTSD in participants who had experienced TBIAmygdala

Amygdala is an area in the brain that underlies fear processing and expression

Amygdala hyper-responsivity in PTSD has been reported during the presentation of personalized traumatic narratives (Shin et al., 2004) and cues (Driessen et al., 2004) combat sounds (Liberzon et al., 1999) combat photographs (Hendler et al., 2003) and trauma-related words (Protopopescu et al., 2005).

Patients with PTSD from 9/11 viewing pictures from the attack (Silbersweig)


Stress and memory 2
mPFC explicit memory of the traumatic event and subsequent development of PTSD in participants who had experienced TBI

Involved in inhibitory control , underactive in PTSD patients (Lanius, Bluhm, Lanius, & Pain, 2005).

PTSD pathophysiology, specifically as failures of midline prefrontal regions to inhibit subcortical limbic, especially amygdala, reactivity (e.g., Milad, Rauch, Pitman, & Quirk, 2006)


Stress and memory 2

Question… explicit memory of the traumatic event and subsequent development of PTSD in participants who had experienced TBI

Are brain alterations associated with PTSD 1)Pre-existing vulnerability factors or 2) acquired signs?

TRAUMA

Brain Differences

PTSD

Brain Differences

PTSD


Hippocampus
Hippocampus explicit memory of the traumatic event and subsequent development of PTSD in participants who had experienced TBI

Area involved in learning and memory and particularly implicated in rich recollective autobiographical memories (Addis et al., 2004).


Hippocampal volume reduced in ptsd
Hippocampal explicit memory of the traumatic event and subsequent development of PTSD in participants who had experienced TBIVolume: Reduced in PTSD

  • Bremner et al., (1995) Vietnam veterans with (n = 26) and without PTSD (N = 22). PTSD subjects had 8% smaller right hippocampus volume & poorer performance on verbal memory measurements (Wechsler Memory Scale).

  • Bremner et al., (2003): 22 female adult survivors of childhood abuse with PTSD (N = 10) or without PTSD (N = 12). PTSD had 15% smaller hippocampal volume than abuse subjects without PTSD. No difference in memory measures.

  • Stein et al., (1997) assessed hippocamalvulume in 21 female adult survivors of severe childhood sexual abuse and 21 control subjects, and also administered cognitive tests (e.g. CVLT). Abuse subjects had 5% smaller left hippocampus size, but no differences or correlations were found on cognitive performance.


Stress and memory 2

Nature Neuroscience5, 1242 - 1247 (2002) Published online: 15 October 2002; | doi:10.1038/nn958

Smaller hippocampal volume predicts pathologic vulnerability to psychological trauma

Mark W. Gilbertson1,2, Martha E. Shenton2, 3, 4, Aleksandra Ciszewski4, Kiyoto Kasai4, Natasha B. Lasko1, 2, 5, Scott P. Orr1, 2, 5 & Roger K. Pitman2, 5

Does this represent:

1) neurotoxic effect of trauma

2) a pre-existing condition that renders the brain more vulnerable to the development of pathological stress responses?


Stress and memory 2

PTSD+ explicit memory of the traumatic event and subsequent development of PTSD in participants who had experienced TBI

PTSD-

Trauma-Exposed

Trauma-UnExposed

A Replication of previous research

B Neurotoxicity Effect

C Pre-existing Vulnerability


Stress and memory 2

PTSD + explicit memory of the traumatic event and subsequent development of PTSD in participants who had experienced TBI

PTSD -

Exposed

Un-Exposed


Stress and memory 2

Combat Exposed explicit memory of the traumatic event and subsequent development of PTSD in participants who had experienced TBI

Combat Un-Exposed

PTSD Severity


Hippocampus conclusions
Hippocampus: Conclusions explicit memory of the traumatic event and subsequent development of PTSD in participants who had experienced TBI

  • Smaller hippocampus in veterans with PTSD

  • Smaller hippocampus in PTSD represents a pre-existing, familial vulnerability factor rather than neurotoxic product of trauma and PTSD development


Triad of structures
Triad of Structures: explicit memory of the traumatic event and subsequent development of PTSD in participants who had experienced TBI

Amygdala

Fear

mPFC

Hippocampus

Memory

Inhibition


Stress and memory 2

Question… explicit memory of the traumatic event and subsequent development of PTSD in participants who had experienced TBI

Does altered neurocircuitry in PTSD patients contribute to the maintenance of fear memories?


Stress and memory 2

CS explicit memory of the traumatic event and subsequent development of PTSD in participants who had experienced TBI+ E

CS +


Stress and memory 2

? explicit memory of the traumatic event and subsequent development of PTSD in participants who had experienced TBI


Impaired safety memories
Impaired safety memories explicit memory of the traumatic event and subsequent development of PTSD in participants who had experienced TBI

  • PTSD patients are not able to retain safety information (e.g. impaired extinction recall Milad et al., 2009).

    • > Can lead to the maintenance of fear memories

  • This is a consequence of getting PTSD, and not a predisposing factor (Milad et al., 2008)


Summary
Summary explicit memory of the traumatic event and subsequent development of PTSD in participants who had experienced TBI

  • Memory for the original trauma

    • Not stable over time

    • Increased memory change predicts PTSD

  • Lack of memory for the trauma is protective against subsequent PTSD

  • Preliminary evidence that PTSD can be treated via interventions that specifically target memory

  • Altered neurocircuitry in PTSD

    • Triad: Amygdala, mPFC and Hippocampus

    • Smaller hippocampus is a predisposing factor

    • Altered neurocircuitry can lead to the maintenance of fear memories


Thank you

Thank you. explicit memory of the traumatic event and subsequent development of PTSD in participants who had experienced TBI

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Applied Cognitive Psychology