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Anxiety

  • Mental state in anticipation of a threat
    • Evolved to protect us from danger
  • Disorder, if this mental state in anticipation of a threat is inappropriate
    • Due to a genetic and environmental interaction
    • Susceptibility is determined early in life – upbringing
      • Median ages of onset:
        • Specific phobias: 6, social phobias (scared of social judgement): 10-12. Median age of onset of disorders - 11 years
        • OCD, panic disorders: late teens
        • Post-traumatic stress disorder, generalised anxiety disorder: late 20s-30s
        • Disorders of young people
        • Models of internalising and externalising fear can explain various manifestations
  • Irrational worrying is anxiety disorder
  • On a good day, the people with these diseases say they'd never be like that, but during a problem period, they are like that.

Having an anxiety disorder is not the same as being too anxious

Symptoms – fight or flight

  • Varied
  • Anxious anticipation
  • Shortness of breath – increased respiration
  • Nausea – blood to muscles away from gut
  • Cold sweats – increased sweating
  • Palpitations – increased heart rate
  • Shaking/trembling – increased muscle tension
  • Selective intension/inattention – mental arousal (e.g. don't feel pain while running from tiger)
  • Light too bright – pupils dilate

Once you've started running, this is not abnormal at all, but before you've started running it's not good.

Yerkes-Dodson curve

  • Anxiety can be facilitating and debilitating depending on its level
    • Can be used to examine performance, judgement of complex situations, perceptions of new information
  • Ie. it’s good to have a small amount of anxiety to increase function, but too much can lead to dysfunction

Anxiety facilitates performance. The extremes of anxiety debilitate (and people wouldn't know what time of day it is).

State anxiety

  • How anxious you feel at the present time
  • Determined by:
    • Level of threat/challenge – ie. no threat, no anxiety
    • Trait anxiety/neuroticism (inherited) – personality, 'how anxious' a person you are
    • Ability to cope – managed by appraisal, problem solving, de-arousal, social support

Trait anxiety

  • Stable across lifespan
    • Correlation with 4, 8, 12 month and 20 year surveys
  • Largest single risk factor for anxiety disorders
    • Brain structures are different
    • Under genetic control

Coping

  • Methods:
    • Appraising accurately - don't get your knickers in a knot for no reason
      • Don't worry about things that aren't a threat to you
    • Preparing to combat, confront, don’t avoid
      • If there is a threat to you, confront the threat
    • Control fear
    • Recruit social support
      • Allies are a great asset if things aren't good
    • Ability to cope depends on the level of threat and trait anxiety Note: symptoms can facilitate further anxiety

* flow diagram trait anxiety

  • Relation between level of threat, state and trait anxiety, coping and position on the Yerkes-Dodson curve
    • People who have symptoms and who don't know physiology will consider the symptom
    • High trait anxiety --> low amount of danger will give you a high level of anxiety; low trait anxiety --> high amount of danger, there is a small amount of arousal

Fear circuits

  • Potential threat/challenge --> Thalamus
    • Thalamus --> amygdala
    • amygdala-->hippocampus
    • amygdala-->frontal cortex
  • Parts:
    • Striatum – to do with active coping
    • Peri aqueductal grey – to do with passive fear
  • ~50%-60% of anxiety (neuroticism) is under genetic control; less than the genes behind alcoholism, Huntington's, schizophrenia

Gross and Hen - Developmental Origin of Anxiety (Nature Reviews)

Serotonin

  • ss polymorphism in serotonin transporter (5-HTT)
    • Associated with:
      • Depression
      • Anxiety
      • Neuroticism, increased trait anxiety
      • Occurs in up to 30% of the population

This is just one of the genetic pathways that can be affected in disease

Maternal influences

Poor parenting can result from anxiety of the parents.

  • Maternal anxiety can lead to anxiety in the adult offspring
    • Genetics is thought to be more important than environment, however in some cases, the environment can override
    • Anxious mother mouse with anxious mother mouse kids = anxious kids
    • Normal mother mouse with normal mother mouse kids = normal kids
    • Anxious mother mouse with normal mother mouse kids = normal kids (genetics)
    • Normal mother mouse with anxious mother mouse kids = normal kids (environment)

Upshot is that both genetics and environment must be pathological to cause anxious children.

Children

  • Sexual abuse is associated with increased anxiety, and in particular increased rates of post-traumatic stress disorder
    • there is a dose response relationship that is independent of other neglect and abuse. Rape before puberty is worst (has an effect above and beyond that of other stimuli)
    • +morphologically, decreased hippocampal size (fMRI)
  • Post-traumatic stress disorder (PTSD) – instrinsic memories of trauma
    • Due to trauma and biology
      • 15% of people who experience a traumatic event get PTSD
    • Have smaller hippocampus
      • Vulnerability factor or effect of trauma? cause or effect?
      • Reduced hippocampus with reduced ability to cope with trauma and reduced with trauma
    • Twin study
      • Small hippocampus before trauma, one trauma
      • PTSD; other no trauma, no PTSD
      • Small hippocampus --> predisposed to PTSD if you have a traumatic experience (won't develop it if no traumatic experience)
  • Much unknown

Adult life

  • Neuroticism decreases with:
    • Age
    • Treatment with SSRIs
      • Suppress propensity to arousal
    • CBT
      • Teaches how to cope
    • Repetitive exposure to controlled stressors
        • Eg. exchange students vs non-exchange students
  • Mature, emotional age of 28, increased coping due to controlled stress exposure
  • Trait anxiety, if reduced, greatly reduces symptoms
    • Thus trying to treat with CBT the ‘risk factors’ for trait anxiety
  • If you give SSRIs and CBT then you can give a semi-permanent change in the trait anxiety of the person (plastic changes)
  • Going overseas your neuroticism score goes down by 0.5 of standard deviation - go away at age 17, come back 18 but emotional level of 28 years old. Sheltered and looked after in a family, but had to manage in a different language. They grow up faster and neuroticism is reduced

Summary

  • Anxiety is useful
  • Symptoms are the flight or fight response
  • Can facilitate or debilitate performance
  • Managed by appraisal, problem solving, de-arousal
  • Causes of anxiety disorders (median age of 11 (3-20)
    • Genetics - neuroticism
    • Early childhood environment - neglect and trauma
    • Adult environment - trauma and poor coping
    • Or all three
  • 1. What is the threat 2. Appraise the threat 3. Work out an appropriate response 4. Carry out the response 5. Reappraise the threat