PTSD Flashcards
What is PTSD?
- A psychiatric disorder that develops in individuals following exposure to a traumatic event.
- Memories of this traumatic event are continuously re-experiences in an intrusive and distressing manner, causing avoidance, dissociative reactions and increased arousal and stress responses.
- PTSD has dramatic consequences in daily functioning and leads to the development of associated pathologies like depression, aggression, substance abuse and high risk of suicide.
What is the Diagnostic & Statistical Manual-5 Criteria for PTSD?
- Exposure to death, threatened death, actual or threatened serious injury, or actual or threatened sexual violence, in either of the following way(s): direct exposure, witnessing the trauma, learning that the trauma happened to a close relative or close friend, indirect exposure to aversive details of the trauma (professional duties - first responders, medics)
- Persistent re-experience of traumatic event, in either of the following way(s): unwanted upsetting memories, nightmares, flashbacks, emotional distress after exposure to traumatic reminders, physical reactivity after exposure to traumatic reminders.
- Avoidance of trauma-related stimuli.
- Negative thoughts or feelings. (overly negative thoughts about oneself, exaggerated blame for causing the trauma, negative affect, decreased interest in activities)
- Trauma-related arousal and reactivity. (irritability, aggression, risky or destructive behaviour, hyper-vigilance, heightened startle reaction, difficulty concentration, difficulty sleeping)
- Symptoms last for more than 1 month. (can start as soon as trauma is experienced or develop over time, but they need to be persistent, otherwise it is considered to be acute stress disorder)
- Symptoms create distress or functional impairment.
- Symptoms are not due to medication, substance use or other illness.
What are examples of Traumatic events that can lead to PTSD?
- war
- natural disaster
- childhood neglect
- physical abuse
- sexual abuse
- sudden death of a loved one
What is the lifetime prevalence in Canada of PTSD?
9.2%
Is PTSD more prevalent in men or women?
- twice as high in women
- being a women is a risk factor
what are other risk factors of PTSD?
- family history of PTSD or depression
- early life trauma
- high stress levels
- lack of support following trauma
is risk of suicide higher in individuals with PTSD?
yes 2- to 3-fold higher
Individuals suffering from PTSD show both enhanced and impaired learning and memory. What are examples of each?
- Enhanced Memory for Traumatic Events (vivid memories of traumatic event, strong emotional recall of said memory)
- Impaired:
- Difficulty with general memory (increased forgetfulness and difficulty recalling everyday events)
- Impaired learning
- Reduced memory flexibility (over-reliance on habitual thought patterns)
- Impaired extinction learning (difficulty extinguishing learned fear responses)
- Attention and concentration issues due to hyper-vigilance.
What is the difference between learning and memory?
- Learning: a change in behaviour that results from acquiring knowledge about the world.
- Memory: the process by which that knowledge is encoded, stored, and later retrived.
What did patient H.M. reveal about the hippocampus and episodic memory?
H.M. (studied by Brenda Milner) lost the ability to form new long-term episodic memories after bilateral medial temporal lobe (including hippocampus) resection. However, his short-term memory, old memories, and motor learning remained intact—showing that multiple memory systems exist in the brain.
Can you explain the different types of memory and how they influence our actions and behavior etc.?
Memory ->
- STM (working memory)
- LTM
-> Explicit (conscious)
1. Semantic (facts & concepts)
2. Episodic (experienced events)
-> Implicit (unconscious)
1. Procedural (skills & actions)
2. Emotional (classical conditioning)
What are the different stages of memory processing?
- Sensory Input ->
- Encoding (requires attention) ->
- Working Memory (limited storage capacity, labile) ->
- Consolidation ->
- LTM (Stable, unlimited storage capacity) <->
- Retrieval (recall of multiple ‘bound’ memories stored in different brain regions into a single percept. It’s a constructive process subject to distortion)
What is auditory fear conditioning?
A learning process where an animal associates a neutral sound (tone) with an aversive stimulus (shock), leading to a fear response (freezing) when the tone is later played alone.
What happens during the three phases of auditory fear conditioning?
- Habituation (Day 1): Tone is played alone (no shock, no fear).
- Conditioning (Day 2): Tone and shock are presented together (association forms).
- Testing (Day 3):
- Tone alone (previously paired) → High freezing (fear response).
- Unpaired tone & shock (separate) → No freezing (no learned fear).
What brain areas process the tone and shock in auditory fear conditioning?
Tone (Direct): Auditory Thalamus -> Amygdala (Lateral Nucleus/Central Nucleus)
Shock (Direct): Somatosensory thalamus -> Amygdala (Lateral Nucleus/Central Nucleus)
Tone (Indirect): Auditory Thalamus -> Auditory Cortex -> Amygdala (Lateral Nucleus/Central Nucleus)
Shock (Indirect): Somatosensory thalamus -> Somatosensory cortex -> Amygdala (Lateral Nucleus/Central Nucleus)
What role does the amygdala play in fear conditioning?
- Lateral nucleus (LA): Receives sensory input (tone & shock) and forms associations.
- Central nucleus (CE): Sends outputs that trigger fear responses.
What are the three major outputs of the central nucleus of the amygdala?
- PAG: causes freezing behaviour.
- Lat. Hypo T: Controls autonomic responses (heart rate, blood pressure)
- PVH: triggers stress hormone release (cortisol)
What are the two types of synaptic potentiation?
- Short-Term Potentiation (STP): A temporary increase in synaptic strength lasting seconds to minutes.
- Long-Term Potentiation (LTP): A persistent strengthening of synaptic connections, lasting hours to days, critical for learning & memory.
What happens when PKA (protein Kinase A - enzyme activated by cAMP) gets inhibited?
Prevents the maintenance of LTP, meaning synaptic strengthening is not sustained over time.
What is an example of a plasticity mechanism?
- AMPA receptors depolarize the postsynaptic membrane, removing the Mg2+ block from the NMDA receptors.
- NMDA receptors then open in response to glutamate, allowing Ca2+ influx.
- Ca2+ activates kinases (e.g., PKA, CaMKII), which insert new AMPA receptors into the postsynaptic membrane, leading to stronger synaptic currents.
How does synaptic potentiation transition from short-term to long-term potentiation?
- Ca2+ influx through NMDA receptors triggers intracellular signalling.
- B-adgrenergic receptors (B-AR) -> AC (adenylate cyclase) -> increases cAMP -> activates PKA.
- PKA activates MAPK activate CREP, TF.
- CREB binds CRE (cAMP response element) sites in DNA, promoting mRNA synthesis.
- mTOR regulates protein synthesis, strengthening synapses.
- Epigenetic changes help sustain LTP over time.
- STP only needs existing proteins, but LTP needs new gene transcription & protein synthesis.
What is the outdated view of Memory Retrieval?
Memories are stored/consolidated once. Each time the memory is activated (remembered) a trace of the original experience is retrieved.
What is the current reconsolidation view of memory retrieval?
- each time memory is retrieved, it becomes labile again (susceptible to change) before it becomes RE-CONSOLIDATED.
- the next time the memory is activated, the version stored during the last retrieval, rather than the version stored after the original experience, is called up.
- this means that memories can be modified each time they are recalled.
What are different psychotherapies used to treat PTSD?
- Cognitive behavioural therapy (CBT)
- learn to identify thoughts, feelings or situations that trigger PTSD. - Exposure therapy.
- Learn to face the thoughts, feelings or situations that trigger PTSD by direct (careful & gradual) exposure. - Cognitive processing/restructuring therapy.
- Aims to replace irrational/dysfunctional (but understandable) patterns of thought with more realistic and helpful ones.
What are pharmacotherapy treatments for PTSD?
- Selective Serotonin Re-uptake Inhibitors (SSRIs) & Serotonin and Noradrenaline Re-uptake Inhibitors, which are classically prescribed for depression.
- Atypical antipsychotic drugs have shown some efficacy as anti-anxiety medications.
What are two types of emerging PTSD treatments?
- Consolidation (preventive treatment)
- Reconsolidation (treatment)
How does Consolidation therapy work?
-> Seeks to prevent the development of PTSD by interfering with the
consolidation process.
-> Pharmacological: Medications like propranolol, a beta-blocker, can be
used to disrupt the consolidation process.
-> Behavioral: Engaging in competing tasks during recall to interfere with
the consolidation of traumatic memories.
How does reconsolidation therapy work?
- seeks to modify a stable traumatic memory by recalling it (rendering it labile again)
- then modify its reconsolidation into a memory with diminished emotional impact.
- though many molecular mechanisms underlying consolidation & reconsolidation are shared, some are specific, raising hope that reconsolidation can be targeted separately.
What are pharmacological ways to perform reconsolidation therapy?
- Propranolol also disrupts reconsolidation of emotional memories in amygdala,
but not of other aversive memories (i.e. those mediated by hippocampus) - Translation blockers (Rapamycin) which effectively blocks the reconsolidation of
hippocampal- and amygdala-dependent threat memories in animal models - Psychedelics like MDMA and ketamine are being explored as a potential
treatments for PTSD
What are behavioural ways to perform reconsolidation therapy?
- Extinction learning is standard treatment for anxiety disorders. Effects often temporary, and traumatic memories can re-emerge in response to other CSs.
- Behavioral protocols are experimented with to better target reconsolidation,
approximately 4 hrs after recall (as opposed to immediately), possibly in
combination with pharmacological therapy.
What are limitations of treating PTSD?
- PTSD associated with very strong, persistent maladaptive memories that are difficult to tamper with using reconsolidation therapy.
-> Animal models use mild, controllable fear (e.g., shocks), unlike real traumatic events, which may engage different brain circuits.
-> Trauma can create uncontrollable states of fear and panic, making extinction difficult.
-> Early intervention is key—treatments are less effective in older traumas (e.g., Vietnam veterans vs. recent conflicts).
