5 - generalised anxiety disorder Flashcards
what does the Yerkes-Dodson Law describe?
how anxiety affects performance
when is anxiety abnormal?
- excessively intense/disproportionate to the stimulus
- triggered by harmless situations, or occurs without a cause
- continues beyond exposure to danger
- cant be controlled
- causes severe distress
- impairs functioning
what is GAD diagnosied in current systems (DSM5, ICD 11)?
- a person must experience (a) a certain number of symptoms for (b) at least a minimum specific period
- the symptoms must cause : significant stress, be associated with impairment in everyday function
—> persistent fear and worry plus at least 3 of:
- poor concentration
- restlessness
- fatigue
- muscle tension
- initial (ie difficulty getting to sleep) insomnia
—> symptoms for >6 months
what must be excluded when diagnosing GAD?
- alcohol or street drug misuse
- hyperthyroidism
- phaeochromocytoma = benign tumour of the adrenal glands
what are psychological symtpoms of GAD?
- constant worries, intrusive thoughts
- feeling of apprehension and dread
- poor concentration
- if severe — depersonalisation, derealisation
what are physical symptoms of GAD?
- tremor, sweatiness, “butterflies”, dry mouth, palpitations
- muscular tension, tension headache
- hyperventilation — difficulty taking a breath, “atypical chest pain”(doesnt radiate, not crushing, often on LHS), parasthesiae in hands, feet and lips (resp alkalosis)
what are some behavioural symptoms of GAD?
- putting things off because of anxiety
- avoidance of particular situations
- “self-medication” — misuse of drugs or alcohol to relieve anxiety
who is GAD more common in?
- more common in women (lifetime prevalence women:men = 5.3% : 2.8%)
- onset commonly in young adult life (median age of onset = 30 years)
- often not recognised partly because patients often present with physical symptoms
a first degree family history of GAD increases the risk how much?
x 2.5
what molecular genetics are associated with GAD?
- several risk genes eg. chromosome 2p21, 2q12
- eg. serotonin transporter gene
what do functional MR imaging studies show in people with GAD?
overactive amygdala (= in temporal lobe, important in fear and anxiety)
what is the main inhibitory neurotransmitter in the mammalian CNS, present in 1/3 synapses?
GABA = y-Aminobutyric acid
how is GABA synthesised?
decarboxylation of the amino acid glutamic acid
what does GABA play a major role in?
regulating neuronal excitability and muscle tone
GABA is the endogenous agonist at what 2 main receptors?
- GABAA receptor - in brain (has multiple ligand binding sites_
- GABAB receptor - in peripheral nervous system
what is a GABA analogue which acts as a selective agonist at GABAB receptors, used clinically as a muscle relaxant?
baclofen