11.1 anxiety Flashcards
what system mediates the stress response(which causes feelings of anxiety?)
the limbic system
has both neural and endocrine targets
what are the neural elements of the stress response (limbic system?)
hippocampus
- receives inputs from cortex and processes emotional content
- ultimately projects to the thalamus (and then back to cortex - papez circuit) as well as the hypothalamus
- hypothalamus causes autonomic features of emotional response as it sends projections down to autonomic preganglionic neurones (hypothalamospinal tract) = sympathetic activation, and adrenaline is released from adrenal medulla = stress response
the amygdala
- sits near hippocampus
- receives inputs from sensory system
- outputs to cortex and hypothalamus
- involved in behaviour and emotional response
pre frontal cortex
- modulaton of emotional reponse
- perception of emotion
what are the endocrine elements of the stress response (limbic system)?
the limbic system is able to act on the hypothalamus to stimulate secretions of stress hormones via hypothalamo-pituitary- adrenal axis
release of cortisol from the adrenal cortex is part of the chronic stress response
what are the symptoms of anxiety?
palpitations sweating dry mouth trembling or shaking difficult breathing chest pain/discomfort nausea/abdominal distress feeling dizzy, unsteady, faint or light headed
what adaptations does the body undergo in prolonged exposure to stressors?
1) the alarm reaction
release of adrenaline and cortisol as well as sympathetic activation. NA and adrenaline released from medulla and cortisol is released from adrenal cortex.
2) resistance (effect of adrenaline starts to wear off)
chronic stress response, prolonged release of cortisol = maintenance of stress response
3) exhaustion (when you cant escape an ongoing stressor)
chronic side effects of prolonged cortisol secretion starts to occur e.g muscle wasting, suppression of immune system and hyperglycemia
where is the hippocampus?
curved piece of cortex folded into the medial surface of the temporal lobe
occupies the floor of the temporal horn of the lateral ventricle
its involved in memory and expression of emotion
where is the amygdala found?
buried in the roof of the lateral ventricle
collection of nuclei
drive related behaviours and processing of associated emotions
how does the limbic-hypothalamal-pituatary adrenal axis work?
cortex -> limbic structures -> hypothalamus
hypothalamus releases corticotropin releasing hormone to the pituitary gland
pituitary gland releases adrencorticoptropic hormone which goes to the adrenal gland
adrenal gland releases cortisol
what are the actions of cortisol?
- increase energy metabolise levels
- suppresses immune system
- inhibition of allergic and inflammatory processes
give 6 classifications of anxiety disorders.
1) social phobia
2) specific phobias e.g spiders
3) generalised anxiety about a variety of things (can lead to…)
4) panic disorder - recurrent, unexpected panic attacks (severe episodes of acute stress response)
5) obsessive compulsive disorder (OCD)
6) post traumatic stress disorder (PTSD)
how can benzodiazepines treat anxiety?
GABA is the main inhibitory neurotransmitter
GABA levels are low in the cortex in patients with a panic disorder
benzodiazepines increase GABA transmission so reduce anxiety
how can serotonin be used to treat anxiety?
use Selective serotonin reuptake inhibitors (SSRIs). This will increase serotonin levels in the brain.
This may stimulate serotonin receptors in hippocampus = neuroprotection, neurogenesis and reduction of anxiety
what is used to treat anxiety?
BIOLOGICAL
- Selective serotonin reuptake inhibitors (SSRIs)
- Short term benzodiazepines (can grow resistant)
PSYCHOLOGICAL
- cognitive behavioural therapy
SOCIAL
- support groups, charities, etc.
what is the epidemiology of OCD?
1/50 will suffer at some point
3/4 of cases start by age 30
what is the difference between obsessions and compulsions?
obsessions
- thoughts that persist and dominate an individuals thinking despite their awareness that the thoughts are either entirely without purpose, or have persisted and dominated their thinking beyond the point of relevance or usefulness
- Unpleasant or repugnant, often causing anxiety
compulsions
- a motor act
- acting out a compulsion may relieve anxiety caused by obsession, but frequently carrying out the compulsion is also unpleasant
