L11 & L12 - Anxiety Flashcards
What is the difference between anxiety and fear?
Anxiety - diffuse unpleasant vague sense of apprehension in anticipation of a future threat
Fear - the emotional response to a real or perceived immanent threat
Fear is associated with surges in arousal (fight or flight) whereas anxiety is preparation for future dangers and avoidance behaviours
Those with anxiety disorders typically overestimate the danger in situations they fear and avoid them
What are the other disorders associated with anxiety?
Anxiety disorders:
phobias
social anxiety
panic disorder
anxiety disorder
Obsessive Compulsive Disorder:
Trauma and Stress Related Disorders
PTSD
What are the shared core symptoms of these disorders?
Fear
Escape
Avoidance
What are the genetic features of anxiety disorders?
29% prevalence
First degree relatives are more likely to have the same anxiety disorder
What are the gene-environment interactions?
PTSD - need the gene and a traumatic experience to trigger the disorder
Animal model example - only when the genes and behaviour (prenatal and postnatal) are present does it have that affect pups behaviour
What is the classical fear conditioning in anxiety?
A fear response can be induced using a phobia and record neural activity to see what is happening at this time
Exposure therapy
Desensitisation
What is the Mowrer two factor theory?
Fear to stimulus is acquired through classical conditioning
Light - shock pairings
Instrumental conditioning allows animals to escape shock or postpone encountering the aversive stimulus
CS + response - no shock (negative reinforcement)
Avoidance is critical in the maintenance of anxiety, because each time subjects encounter the CS, they avoid it so they never experience it
How does fear and avoidance interlink?
Fear leads to avoidance
No fear leads to no avoidance
Treatment is orientated around fear
Bidirectional relationship between the two
What is the amygdala and its role in the neural system?
It is involved in the fear reaction to a threat
Amygdala is overactive in anxiety states
The current focus is on a fear network rather than a single structure
Hub in the wheel of fear
Signals in the amygdala reduces during extinction
How does the amygdala link to fear and avoidance behaviour?
Increased signal in central amygdala during avoidance
Fear is processed in the amygdala
Those with high trait anxiety showed increased amygdala response to fear cues
Spider phobics showed increased amygdala response compared to controls
How does OCD and reversal learning interlink?
Fear conditioning reversal learning
OCD patients learned on the discrimination early on but failed to discriminate following reversal
Failure to reverse contingencies
Higher PFC activation predict generalisation during reversal
What is the evolution of treatments for anxiety disorders?
Sedatives - barbiturates, benzodiazepine, selective GABA agonists
Non-sedatives / antidepressants
Can experience withdrawal symptoms
What are benzodiazepines?
e.g. librium, chlordiazepoxide, valium, diazepam
Anxiolytic use mainly in Generalised Anxiety Disorder and acute stress reactions
Also used as anti-convulsants and hypnotics
Low toxicity - high safety ratio, unlike the barbiturates which they replaced
Disadvantages include:
- withdrawal syndrome (e.g. insomnia, anxiety, loss of appetite)
- impairment of cognitive performance
What are the correlations between BZD and brain regions?
Limbic and prefrontal cortex - anxiolytic
Cortex, hippocampus, amygdala - anti-convulsant
Ventromedial hypothalamus - appetite stimulant
Cerebellum - ataxia
How does the amygdala respond to fearful faces?
Those with short allele of the serotonin transporter shows increased amygdala responses to fearful faces
Amygdala response is reduced with 8 weeks of SSRI treatment
