Post traumatic stress disorder

What is the statistic for how many people experience a traumatic event in their lives

1 in 3 people

What are the symptoms and criteria

• stressor event

• Intrusion symptoms

• Alterations in arousal/ reactivity

• Negative alterations in cognition/ mood

• Avoidance behaviour

What is complex PTSD

Trauma related to multiple events over an extended period of time

What is stressor

• direct exposure

• Witnessing trauma

What is alterations in arousal/ reactivity

• irritability

• Destructive behaviour

• Hyper vigilance

What are intrusion Symptoms

• memories

• Nightmares

• Flashbacks

• Emotional distress as a response to reminders

What is negative alterations in cognitions/mood

Negative thoughts or feelings that began or worsened after trauma

• inability to recall key features

• Negative assumptions/ thoughts about self/world

• Isolation

• Decreased interest in activities

What is avoidance

Avoidance of trauma related stimuli after trauma

• trauma related thoughts or feelings

• Trauma related external reminders

What brain axis responds to stress

Hypothalamic-pituitary-Adrenal Axis

What happens in the HPA upon exposure to stress

1. Hypothalamus released cortiotropin-releasing hormone

2. This stimulates the anterior pituitary gland to produce adrenocorticoreopin (ATCH)

3. ACTH then stimulates the release of cortisol (glucocorticoids) from the adrenal gland

4. The glucocorticoids the modulate metabolism, immune response and brain function, preparing you for fight or flight response

How many brain pathways modulate HPA axis activity

Several

What inhibits the HPA Axis

Hippocampus and prefrontal cortex

What stimulates neurones in the hypothalamus

The amygdala

How does the glucocorticoids exert negative feedback control of the HPA Axis

By regulating hippocampus and hypothalamus neurones

What sustained exposure negatively impacts the brain

Sustained exposure of cortisol

What are the 4 symptom clusters of in PTSD

1. Intrusions

2. Avoidance

3. Cognition and Mood

4. Arousal and reactivity

What is included in all 4 symptom clusters of PTSD

Amygdala

What did Etkin and Wagners fMRI meta-analysis find

all studies examined brain activity when attending to a disorder relevant stimuli

• Patients with any of the three disorders showed greater activity than matched comparison subjects in the amygdala and insula

• PTSD specifically showed hypo activity in prefrontal cortex, thalamus, and cingulate

What did Louge et al find in his meta analysis about PTSD and Hippocampal volume

A smaller hippocampus = increased chance of having PTSD

What did Gilbertson et al find in there MZ twin study on hippocampal volume and trauma

• hippocampal volume predicted severity of PTSD in combat twin and non-combat exposed twin

• Smaller hippocampus increases likelihood of mental illness

What does human post-mortem data show in the hippocampus, what does this impair and demonstrate

Shows a decreased BDNF in hippocampus

• impaired memory process

• Demonstrates neuroplasticity at a specific anatomical level

What is the hippocampus involved in during ‘online’ states such as learning or memory tasks ?

Encoding or retrieving memories

What does the hippocampus do during ‘offline’ states such as sleep or rest

Spontaneously replays previously encoded information

What did Liu et al use MEG to show

To show memory replay during periods of rest in humans

How does hippocampus activity during rest periods link to PTSD

Spontaneous replay of traumatic memories could trigger memory intrusions and ‘flashbacks’ in PTSD

What is Think/no think Paradigm (TNT)

An experimental task to test memory suppression ability

What did Catarino use TNT to do and what was found

Used the TNT to compare memory supppression in PTSD patients compared with trauma exposed controls

• found that PTSD patients showed worse memory suppression

• Memory suppression ability correlated with thought control ability and PTSD symptoms

When does the Dorsolateral prefrontal cortex activate

When we engage top-down regulatory control

When does the hippocampus activate

When we retrieve a memory

What was found when Benoit et al questioned if activity will go up and down in the hippocampus and DLPFC when we try to suppress a memory

That successful memory suppression requires increased activation of the DLPFC and decreased activity of the hippocampus

What was Mary et al questioning when she studied memory suppression in survivors of the 2015 Paris terrorist attacks

And what was found

Questioning if memory suppression promotes resilience after trauma

Found

• Think/No-think PTSD and non exposed controls showed suppression of hippocampus by prefrontal control regions

• PTSD showed no top-down suppression of memory retrieval networks

• Memory suppression is a general risk factor that influences vulnerability or resilience to PTSD following a trauma

What is REM and when does it occur

Rapid eye movement

• occurs nearer the end of the night, when vivid dreaming

What is NREM and when does that occur

Non Rapid eye movement

• occurs over the night during growing levels of sleep depth

What are some common sleep disturbances

• insomnia

• Awaking more in the night

• Frequent nightmares

• Disruptive nocturnal behaviours → sleep paralysis, dream enactment

In those with PTSD what happens during sleep

Cortical hyperarousal indexed as increased power in high frequencies

What did Denis ET al find when studying increased levels of cortical hyperarousal during sleep in PTSD patients

Hyperarousal during sleep interacts with other domains of hyperarousal experienced during the day

How does sleep consolidate memory ?

By strengthening memory traces during NREM sleep

• preferably consolidating emotionally charged experiences

What did Denis find when studying sleep enhancing emotional memory

That sleep amplifies memory for negative scene components at the expense of accompanying background information, and reduces emotion reactivity

Van der helm found that following sleep, pps would rate emotional images less emotionally intense, what was this associated with?

This was associated with reduced amygdala activity after sleep, and correlated with amount of time spent in REM sleep

What did Van der helm find with NREM and REM sleep

NREM sleep strengths memory representations

REM sleep reduces affective tone

When did Ben Simon find when studying sleep deprivation and if it induces anxiety

• significantly elevated anxiety levels after sleep deprivation

Showed neg images after sleep deprivation:

• showed greater amygdala activity and reduced PFC activity when viewing negative images

What did Harrington et al find when studying sleep deprivation distrusting top-down memory control

• more intrusions of suppressed memories after sleep deprivation

• Reduced DLPFC activity and increased hippocampus activity during suppression trials

• Sleep deprivation disrupts memory control

What did kleim do to study sleep following stimulated trauma reducing memory intrusions and what was found

Had pps in wake group watch film in morning, those in sleep group watch film in evening then slept at home

Sleep pps reported fewer intrusions and lower associated distress than wake pps

What are first line treatments for PTSD

Psychological therapies

What happens when you pair the conditioned stimulus and unconditioned stimulus

It leads to the conditioned response

What is extinction

The reduction of the conditioned response by repeated presentation of the conditioned stimulus in the absence of the unconditioned stimulus

What did Milad et al find when studying PTSD and trauma exposed control patients undergoing Fear a fear conditioning and extinction paradigm

• No group differences in fear acquisition or extinction learning

• PTSD patients unable to retain memory for extinction 24hr later

In miads’ study on impaired extinction recall in those with PTSD, what was associated with PTSD patients being unable to retain memory for extinction 24hrs later

Reduced vmPFC and hippocampus activity during extinction recall

What is ability to retain extinction dependent on

Good quality sleep

What can enhance extinction recall

More slow oscillations and sleep spindles with good quality sleep

What did kleim et al find about sleep and exposure therapy

That sleeping after an exposure session enhances therapeutic effectiveness

• less fear and fewer negative cognitions

What is eye movement desensitisation and reprogramming

Where patients follow with their eyes a rapidly moving stimulus, whilst holding different aspects of trauma in mind

What does the brain fail to do which causes PTSD to arise

When the brain fails to appropriate consolidate traumatic memories

EMDR changes activity in what

In the PFC, Amygdala, thalamus, and Caudate Nucleus

What is Targeted memory reactivation and how does it work

Is an experimental technique to bias memory reactivation during sleep

• sound cues associated with learning are played back to the Pps whilst they are sleeping

What did van de Heijden find when they played EMDR clicks during periods of slow wave sleep

• Targeted memory reactivation pps showed significant improvements in PTSD avoidance symptoms