11a & 11b.) Anxiety Flashcards
Define anxiety
A feeling of worry, nervousness or unease about something with an uncertain outcome
The stress response, which is repsonsible for feelings of anxiety, is there to help us do what?
Stress response helps us to escape from potentially dangerous situations
What system primarily mediates the stress response?
What are it’s two targets in the stress response?
- Limbic system is primary mediator in the stress response
- Has neural and endocrine targets
Briefly describe what the limbic system is and state some structures in the limbic system
The limbic system is a set of brain structures located on top of the brainstem and buried under the cortex. Limbic system structures are involved in many of our emotions and motivations, particularly those that are related to survival such as fear and anger.
Describe the role of the hippocampus (focus on role in limbic system)
- Receives inputs from many parts of cortex and processes their emotional content
- Ultimately project to thalamus (and hence back to cortex- the Papez circuit) and also to hypothalamus
- When hippocampus projects to hypothalamus it causes the autonomic features of emotional response (e.g. sweat) as the hypothalamus sends projections down through the cord to autonomic preganglionic neurones via the hypothalamospinal tract- leading to sympathetic nervous system activation as well as release of adreanaline form adrenal medulla (acute stress response)
- Role in memory (thought that Papez circuit has role in memory)
Where is the amygdala?
Almond shaped structure sitting near tip of hippocampus
Where does the amygdala receive it’s sensory inputs from and where does it send major outputs to?
- Sensory input from sensory system
- Major outputs to cortex & hypothalamus
What is the role of the amygdala?
Like the hippocampus it is involved in behavioural and autonomic emotional responses (thought that it has particualr role in fear)
Where is the prefrontal cortex?
Is it clasically part of the limbic system?
- See image for where it is
- Not classically part of limbic system but it has definite roles in emotions
What is the prefrontal cortex’s role in emotion?
Thought that it has role in the modulation of emotional response (e.g. consciously supressing features of anxiety)
The hippocampus projects to the hypothalamus and results in activation of sympathetic nervous system via hypothalamospinal tract. However, alongside neural response the hypothalamus is also able to produce an endocrine response during the stress response; describe the endocrine response of the hypothalamus in the stress response
- Limbic system acts on hypothalamus to stimulate it to secrete stress hormones
- Secretion occurs via hypothalamo-pituitary-adrenal axis
- Adrenal cortex releases cortisol and this is part of the chronic stress response
Compare the acute and chronic stress response
What is the general adaptation syndrome?
General adaptation syndrome, or GAS, is a term used to describe the body’s short-term and long-term reactions to stress. It refers to 3 stages teh body goes through during prolonged exposures to stressors
Describe the 3 stages of the general adaptation syndrome
-
Stage 1:
- The alarm reaction
- Release of adrenaline & cortisol as well as sympathetic activation
-
Stage 2:
- Resistance (effect of adrenaline starts to wear off)
- Chronic stress response, prolonged release of cortisol
-
Stage 3:
- Exhaustion (when you cannot escape an ongoing stressor)
- Chronic side effects of prolonged cortisol secretion start ot occur e.g. muscle wasting, supression of immune system & hyperglycaemia
State 2 situations in which the stress response become pathological?
When you cannot escape a stressor(s) or when ‘trivial’ stressors elicit a strong stress response (e.g. things that shouldn’t start a strong stress response do)
What term is used to clinically describe a pathological stress reponse?
Anxiety
State some symptoms of anxiety
Symptoms primarily due to activiation of sympathetic nervous system:
- Palpitations
- Sweating
- Trembling or shaking
- Dry mouth
- Difficulty breathing
- Chest pain or discomfort
- Nausea or abdominal distress
- Feeling dizzy, unsteady, faint or light headed
State the 6 anxiety disorders you need to be aware of
- Social phobia
- Specific phobias e.g. spiders, heights etc…
- Generalised anxiety disorder (persistent anxiety about a variety of things)
- Panic disorder (recurrent, unexected panic attacks [severe episodes of acue stress response])
- Obsessive compulsive disorder (OCD)
- Post-traumatic stress disorder
Discuss the pathophysiology of anxiety disorders
- Unclear
- Brain activation findings are open to more than one interpretation
- GABA levels appear to be low in some anxiety disorders such as panic disorder
- Increasing serotonin levels can help to treat anxiety disoders (so does this mean there is disturbance in serotonin levels?
Explain how benzodiazepines reduce anxiety
- Gaba= main inhhibitory neurotransmitter
- When it binds to GABA receptor it causes chloride channel to open causing influx of Cl-
- This hyperpolarises cell making it more difficult for cell to reach threshold and hence reduced neuronal excitability
- Benzodiazepine bind to GABA receptor and enhances the binding of GABA to help reduce neuronal excitability
How do serotonin reuptake inhibitors work?
Thought that increased levels of serotonin may stimulate serotonin receptors in hippocampus leading to neuroprotection, neurogenesis and reduction in anxiety
Discuss the biopsychosocial model for treating anxiety
- Biological
- Short term benzodiazepines
- SSRIs
- Psychological
- CBT (congitive behavioural therapy)
- Social
- Support groups, charities etc..
Why can benzodiazepines not be used long term?
Cause tolerance and hence withdrawal
