Case 5 - Anxiety lecture Flashcards
what is the Yerkes-dodson law
how anxiety affects performance
when does anxiety become abnormal
excessively intense / disproportionate to the stimulus
Triggered by harmless situations, or occurs without a cause
Continues beyond exposure to danger
Can’t be controlled
Causes severe distress
Impairs functioning
what is the operational diagnosis
to meet a psychiatric diagnosis in current systems (DSM5, ICD11)
- a person must experience (a) a certain number of symptoms for (b) at least a minimum specified period of time
what must the symptoms cause
- significant stress
- be associated with impairment of everyday function
what is classification for GAD
- persistent fear and worry
- plus at least three of:
poor concentration
restlessness
fatigue
muscle tension
initial (start of sleep) insomnia
how long must you have had these symptoms for
more than 6 months
what do u exclude while diagnosing
alcohol or street drug missuse
hyperthyroidism
pheochromocytoma
what is pheochromocytoma
benign tumour on the puituatiry gland
what is the median onset age
30
what are the molecular genetic aetiology
GWAS: several risk genes egg chromosome 2p21, 2q12
candidate gene studies e.g serotonin transporter gene
what is GABA
the main inhibitory neurotransmitter in the CNS
what is GABA synthesised by
decarboxylation of the amino acid glutamic acid
what is GABA’s major roles
regulating neuronal excitability and muscle tone
what are the GABA receptor
GABAa - multiple ligand binding sites
GABAb - baclofen is a GABA analogue which acts as a selective agonist for GABAb receptors. used clinically as a muscle relaxant
features of the GABAa receptor
- transmembrane ligand gates ion channel receptor
- 5 subunits arranged around a central chloride channel
- 5 distinct types of subunit have been cloned to date; alpha, beta, gamma, sigma and p
- GABA binds to the binding pocket between the alpha and beta subunits. this causes CL- ions to flow into the neurone leading to decrease chance of action potential
what is the NICE guidance stepped care approach 1
Step 1: recognition and diagnosis of GAD
Step 2: offer treatment in primary care
interventions with positive evidence base:
Psychological therapy (CBT)
Pharmacological therapy - SSRI or benzodiazepines
Self help (online self education)
shared decision making
what is the NICE guidance stepped care approach 2
Step 3: non-response: review and offer alternative treatment
Step 4: review and offer referral to secondary care
if 2 interventions have been provided and the person still has significant symptoms, then referral to specialist mental health services should be offered
Step 5: care in specialist mental health services
through reassessment
what are the core elements of CBT
- identifies unhelpful patterns of things and how these cause feelings of anxiety
- aims to replace these unhelpful beliefs with more realistic and balanced ones. it mainly focuses on current problems rather than events from the past
- ## the B part is most effective when there are specific environmental triggers
how many sessions of CBT does NICE recommend
12 to 15 one hour long sessions over 4 months
what is first line treatment for anxiety
SSRI’s
benzodiazepines mode of action
bind at a separate site between the alpha and gamma units
this potentiates the action od GABA and increase CL- influx
diazepam is a positive allosteric modulator at the GABAa receptor
how do SSRI’s work
block serotonin re uptake from the synapse
what are the other antidepressants used in GAD
Mirtazapine (blocks pre synaptic alpha-2 auto receptors)
Duloxetine (SNRI)
Venlafaxine (SNRI)
Imipramine (tricyclic)
side effects differ to SSRIs
what is the action of pregabalin
precise action unknown: molecule is structurally similar to GABA. it can bind to the alpha2delta subunit of the calcium channel, decreasing the release of neurotransmitters including glutamate, noradrenaline and substance P
how do benzodiazepines differ
mainly in their half life
- diazepam (valium) 30 hours vs triazolam 2 hours
where do benzos act
at the GABAa receptor
