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
Briefly describe what cognitive behavioural therapy is
Cognitive behavioural therapy (CBT) is a talking therapy that can help you manage your problems by changing the way you think and behave
For OCD, discuss:
- How common it is
- When it starts
- Prevalence in males and females
- 1 in 50 will suffer from it at some point in lives
- 1/3 cases start between 10 and 15yrs, 3/4 of cases started by age 30
- Equal prevalance in males & females
Discuss what OCD is, think about:
- What it is primarily characterised by
- How long characteristics must be present for
- What features of the characteristics must be present
- Primarily characterised by obsessions & 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. Thoughts are often upleasant and regpugnant- causing anxiety
- Compulsions: usually a motor act (but sometimes a thought) resulting from an obsession. Acting out a compulsion may releive the anxiety provoked by its associated obsession but frequently carrying out the compulsion is also unpleasant
- Obessions and/or compulsions must be present on most days for at least 2 weeks
- Obessions & compulsions must have the following features:
- Originate in mind of patient
- Repetitive & unpleasant
- Acknowledged as excessive or unreasonable
- Patient tries to resist, but at least one obession/compulsion is unsucessfully resisted
Discuss the pathophysiology of obsessive compulsive disorder
- Unclear but there are some hypotheses:
- Basal ganglia re-entrant circuits:
- Cortex projects to the basal ganglia and then these project back up to the cortex via the thalamus
- This is an example of a re-entrant loop where obsessional thoughts can re-enter the cortex having entered the basal ganglia
- May be due to overactivity in the direct pathway
- Treatments should inhibit thalamic (and hence cortical) activity by reducing the driect pathway or increasing the indirect pathway
- Reduced serotonin levels (so SSRIs help)
- Altered activity in range of cortical areas
- Autoimmune aetiologies (may be cross-reactivity
- Basal ganglia re-entrant circuits:
What is PANDAS (in terms of OCD)?
- Paediatric autoimmune neuorpsychiatric disorder associated with Streptococcal infection
- Sudden onset of OCD symptoms or tics after infection with Group-A beta haemolytic strep (usally 3-12yrs)
- Dramatic onset of psychiatric or behavioural problems
- Antibodies cross-react with neurons in basal ganglia causing symptoms
- Responds to antibiotics & usual OCD management
Describe the biospsychosocial treatment for OCD
- Biological
- SSRIs +/- antipsychotics
- Deep brain stimulation?
- Psychological
- CBT
- Social
- Family support
- Support groups etc…
Describe what PTSD is
- Repetitive, intrusive recollection or re-enactment of the event in meories, daytime imagery or dreams
- This is conspicuous emotional detachment, numbing of feeling and avoidance of stimuli that might arouse recollection of trauma
- Can occur within 6 months following an exceptionally severe traumatic event
Discuss the pathophysiology of PTSD
- Unclear
- Evidence of amygdala hyperactivity causing exaggerated behavioural responses
- However, low levels of cortisol also found and cortisol usually inhibits traumatic memory retrieval and controls sympathetic response
Describe the biopsychosocial treatment for PTSD
- Biological
- SSRIs
- Maybe short term benzodiazepines
- Psychosocial
- CBT
- Eye movement desensitizatioin reprocessing therapy
- Social
- Charities are particularly active e.g. Help for Heroes
Discuss the difference between neurology and psychiatry
Discuss the difference between organ & functional psychiatric disorders
- Organic= dysfunction of brain e.g. demeinta, psychiatric manifestations of epilepsy, brain injury
- Functional= dysfunction of mind e.g. shcizophrenia, bipolar, anxiety, depression
We often refer to pscyhiatric illnesses as disorders as oppose to diagnoses; why?
Diagnosis suggests we know the underlying cause/pathology. In most psychiatric illnesses we don’t and we label them as disorders based on signs & symptoms
Summarise the classification of psychiatric disorders
- *Psychotic= delusions & hallucinations*
- *Neurotic= anxiety & non-psychotic mood disorders*
