Neuro21 - Anxiety Disorders

Question 1

3 general features of anxiety

Definition
Symptoms x8
Disorders x6

Answer 1

1.) Definition - a feeling of worry, nervousness, or unease about something with an uncertain outcome

2. ) Symptoms
   - palpitations, sweating, dry mouth, shaking, dizziness
   - chest pain, difficulty breathing, abdominal distress

3.) Disorders - generalised anxiety disorder, panic disorder, social phobia, specific phobias, OCD, PTSD

Question 2

5 features of the stress response

Limbic System
Hypothalamus
Adrenal Cortex
Sympathetic Nervous System (SNS)
General Adaptation Syndrome

Answer 2

1. ) Limbic System - regulated by the cortex
   - regulates the hypothalamus
2. ) Hypothalamus - regulated by the limbic system
   - activates SNS and adrenal-cortical system by releasing CRH (HPA axis)
3. ) Adrenal Cortex - regulated by ACTH
   - CRF stimulates pituitary gland to secrete ACTH
   - releases cortisol + other hormones
   - cortisol ↑energy metabolite levels, ↓immune system, ↓allergic and inflammatory processes
4. ) SNS - can be activated by the hypothalamus
   - activates adrenal medulla to make (nor)adrenaline
   - ↑HR and force of contraction, bronchodilation

5.) General Adaptation Syndrome - physiological changes the body goes through when under stress

Question 3

4 structures of the limbic system

Hippocampus
Amygdala
Prefrontal Cortex and Anterior Cingulate Gyrus

Answer 3

1. ) Hippocampus - curved piece of cortex (seahorse)
   - involved in memory and expression of emotion
2. ) Amygdala - collection of nuclei,
   - inputs from: brainstem, thalamus, cortex
   - outputs to: brainstem and hypothalamus
   - drives related behaviours and processing of associated emotions
3. ) Prefrontal Cortex and Anterior Cingulate Gyrus
   - have modulatory effect on processes associated with the hypothalamus

Question 4

3 stages in the general adaptation syndrome

Alarm Reaction
Resistance
Exhaustion

Answer 4

1. ) Alarm Reaction - hormones released
   - (nor)adrenaline release from sympathetic nerves and adrenal medulla
   - cortisol release form the adrenal cortex

2.) Resistance - action of cortisol is longer lasting than adrenaline, allowing maintenance of stress response

3. ) Exhaustion - prolonged stress –> too much cortisol:
   - muscle wastage, ↓immune function, hyperglycaemia

Question 5

4 treatments for anxiety disorders

Answer 5

1. ) SSRIs - ↓serotonin reuptake –> ↑serotonin levels –> ↑stimulation of serotonin receptors in the hippocampus
   - leads to neuroprotection, neurogenesis, ↓anxiety
   - OCD: high dose required and can be augmented with antipyschotics e.g. clomipramine (TCA)
2. ) GABA Analogues - ↑increases amount of GABA
   - ↓GABA levels in cortex of patients with panic disorder
   - pregabalin, benzodiazepines (only used short term)
3. ) Cognitive Behavioural Therapy (CBT)
   - non pharmacological
4. ) Deep Brain Stimulation - stimulates STN
   - can be used for OCD

Question 6

5 features of obsessive compulsive disorders (OCD)

What are Obsessions?
What are Compulsions?
Diagnostic Criteria
Epidemiology
Pathophysiology x3

Answer 6

1. ) Obsession - intrusive thought
   - persistent, dominating thought with no purpose
   - often repugnant, causing anxiety and guilt
2. ) Compulsion - neutralising ritual
   - obessional motor acts mediated by an obsessional mental image or fear
3. ) Diagnostic Criteria - obsession/compulsion both present on most days for > 2 weeks
   - unpleasurable, causes distress or interferes with patient’s social or individual functioning
4. ) Epidemiology - usually begins from 10-30
   - 1/3 starts between 10-15, 75% started by 30
   - childhood OCD is more common in boys

5.) Pathophysiology - re-entry circuits in basal ganglia, reduced serotonin, PANDAS

Question 7

4 stages of OCD re-renty circuits in basal ganglia

Input
Processing
Output
OCD Re-Entry Circuit

Answer 7

1. ) Input - ‘my hands are dirty’
   - from cortical and subcortical areas
2. ) Processing - ‘do I need to wash my hands?’
   - basal ganglia/striatum
3. ) Output - washes hands
   - in a normal person: ‘my hands are now clean and I can carry on with my day’
   - basal ganglia/cerebellum –> PMC –> body part
4. ) OCD Re-Entry Circuit - output –> processing
   - ‘maybe my hands aren’t really clean and I need to wash them again’

Question 8

3 features of PANDAS (paediatric autoimmune neuropsychiatric disorder associated w/ streptococcal infection)

Onset
Pathophysiology
Treatment

Answer 8

1. ) Onset - suddenly after infection w/ Group A beta-haemolytic strep, common in 3-12 years
2. ) Pathophysiology - antibodies cross-react with neurones in basal ganglia causing symptoms
3. ) Treatment - antibiotics, usual OCD management

Question 9

What is post traumatic stress disorder (PTSD)?

Pathophysiology x2

Answer 9

Repetitive, intrusive recollection of a traumatic event in daytime imagery or dreams
- < 6 months of traumatic event of extreme severity

Pathophysiology - hyperactivity of amygdala causing exaggerated response to perceived threat
- low levels of cortisol (cortisol inhibits traumatic memory retreival and controls sympathetic response)