Anxiety Flashcards
Fear is associated with…
surges in autonomic arousal (needed for fight or flight)
Anxiety is associated with…
muscle tension and vigilance in preparation for future danger
Anxiety is characterised by
avoidance behaviours
Individuals with anxiety disorders typically
overestimate the danger in situations they fear or avoid
Anxiety disorders
Specific phobia
Social anxiety disorder (social phobia)
Panic disorder (sometimes + agoraphobia)
Generalised anxiety disorder
Genetics of Anxiety
First-degree relatives are most likely to have the same anxiety disorder as the proband (Fyer et al 1995), but first-degree relatives are also at increased risk for other anxiety disorders
Gene-environment interactions (PTSD)
Normal brain with normal hippocampus - with or without combat experience low risk of PTSD
Susceptible brain with small hippocampus with combat - high risk of PTSD
without combat - low risk of PTSD
Mowrer two-factor theory
Fear to a stimulus is acquired through classical conditioning
Instrumental conditioning (avoidance learning) allows animals to escape shock or postpone encountering the aversive stimulus.
Avoidance is critical in the maintenance of anxiety, because each time subjects encounter the CS, they emit a response to avoid the US (negative reinforcement). When avoidance is high, subjects never experience whether the CS is followed by the US.
Amygdala
Involved in fear reaction to a threat
overactive in anxiety states
decreased activation in Pre frontal cortex
Increased amygdala activation in…
phobics and GAD
Benzodiazepines Advantages
Low toxicity: high safety ratio, unlike the barbiturates which they replaced
Used mainly in GAD and acute stress reactions
Benzodiazepines Disadvantages
the induction of dependence and associated withdrawal syndrome (e.g. insomnia, anxiety, loss of appetite, ),
impairment of cognitive performance e.g. anterograde amnesia
Different types of anxiety disorders
specific phobia
social anxiety disorder
panic disorder
generalised anxiety disorder - multiple situations trigger anxiety response
OCD
PTSD
Lifetime prevalence of generalised anxiety
5%
Lifetime prevalence of panic disorder
3%
Lifetime prevalence of PTSD
3%
Lifetime prevalence of social phobia
13%
Lifetime prevalence of specific phobia
11%
Lifetime prevalence of OCD
2%
what is the population prevalence of all anxiety disorders (Burmeister et al., 2008)
29%
are anxiety disorders heritable?
Yes - concordance rate for panic disorder in MZ twins is 23-73%, for DZ is 0-17% - suggests a genetic component
describe the diathesis-stress model for the development of an anxiety disorder?
first we need a genetic predisposition for an anxiety disorder
- then an environmental stressor which triggers the disorder
what brain structure increases susceptibility for an anxiety disorder?
slightly smaller hippocampus - but only if environmental risk is also there
in Gross et al’s (2004) cross-fostering study into the developmental origins of anxiety in rats, which pups had high anxiety?
pups with low licking mother (genetics) and raised by low licking mother (environment)
what is the clear implication of Mowrer’s (1951) two-factor theory?
fear = avoidance
no fear = no avoidance
describe Whalen et al (2004) study into implicit emotional processing
stimuli presented for 17ms, either fear or happy eye whites - not consciously detected
- happy eye whites show less activation of the amygdala
Describe results of Phelps et al (2004) study into the role of the amygdala and vmPFC in extinction learning?
amygdala: activity decreases as extinction progresses
medial prefrontal cortex: activity increases as individuals learn to inhibit fear responses, directly inhibits activity of amygdala
describe the results of the avoidance learning condition in Prevost et al’s (2011) study into amygdala activation during avoidance learning?
- lateral amygdala encodes reward part of the task
- central amygdala encodes avoidance part of the task
what are phasic fear cues?
a stimulus that triggers a temporary response of fear or anxiety as it is paired with an electric shock
describe results of Kolesar et al’s (2019) meta-analysis into the structural and functional differences in GAD and controls
individuals with GAD had amygdala hyperactivation and PFC hypoactivation
what did Apergis-Schoute et al (2017) find patients with OCD have a deficit in?
reversal learning - once they learn something, they fail to learn these new contingencies
in Apergis-Schoute et al (2017) study into reversal learning, what did an fMRI reveal about OCD patients brain activity in response to the safety signal that was previously fearful?
- over activation of medial prefrontal cortex as have trouble encoding the signal is now safe
- failure to reverse contingencies
- higher PFC activation predicted generalisation during reversal
what does SSRI stand for
selective serotonin reuptake inhibitor
what does SNRI stand for
selective noradrenaline reactive inhibitor
how do SSRIs and SNRIs work
they block the reuptake of serotonin and noradrenaline so that more of the neurochemical ends up in the synaptic cleft, more for the postsynaptic neurone to take up
where are high concentrations of the benzodiazepine receptor found in the brain?
medial prefrontal cortex
