Anxiety Disorders Flashcards
What makes up the stress response?
The limbic system
Limbic-hypothalamo-pit-adrenal axis
What is the limbic system?
Set of structures either side of the thalamus: hippocampal formation, septal area, amygdala, prefrontal cortex, cingulate gyrus
Function = emotion, behaviour, motivation, long-term memory, olfaction
Describe the hippocampus
Curved piece of cortex = subiculum, hippocampus proper, dentate gyrus
Folded into medial surface of temporal lobe
Floor of temporal horn of lateral ventricle
Function = memory, emotion
Describe the amygdala
Buried in roof of lateral venticle
Collection of nuclei
Inputs = sensory info, brainstem, thalamus, cortex
Outputs = cortex, brainstem, hypothalamus
Function = drive related behaviours and processing of associated emotions
What is the role of the prefrontal cortex?
Planning complex cognitive behaviour
Personality expression
Decision making
Moderating social behaviour
Modulatory effect on processes associated with the hypothalamus
What is the role of the anterior cingulate gyrus?
Location = collar around frontal part of corpus callosum
Reward anticipation, decision making, ethics, morality
Modulatory effect on processes associated with the hypothalamus
What are the actions of cortisol?
Increase of energy metabolite levels
Suppression of immune system
Inhibition of allergic and inflammatory processes
Control blood sugar levels
Longer action than adrenaline
Define anxiety
A feeling of worry, nervousness, or unease about something with an uncertain outcome
What are the symptoms of anxiety?
Palpitations
Sweating
Trembling or shaking
Dry mouth
Difficulty breathing
Chest pain or discomfort
Nausea or abdominal distress (e.g. butterflies in stomach)
Feeling dizzy, unsteady, faint or light-headed
What conditions fall under ‘anxiety disorder’?
Social phobia
Specific phobias: spiders
Generalised anxiety disorder
Panic disorder – discrete episodes
Obsessive compulsive disorder
Post traumatic stress disorder
Outline the theories regarding the aetiology of anxiety disorder
GABA (inhib neurotransmitter) levels decreased in cortex
Increased serotonin may stimulate serotonin receptors in hippocampus = neuroprotection, neurogenesis and reduction of anxiety
What is used to treat anxiety disorder?
SSRIs = selective serotonin reuptake inhibitors – increase the amount of serotonin in the synaptic cleft
CBT = cognitive behavioural therapy
Pregabalin = GABA analogue
Describe an obsession
Thought that persists and dominates despite awareness that the thought is either entirely without purpose or has persisted and dominated beyond the point of relevance or usefulness
Describe a compulsion
Obsessional motor act
May be mediated by an obsessional mental image or fear
Outline the diagnosis of obsessional/compulsion disorders
Present on most days for a period of at least 2 weeks
Originate in the mind of the patient
Repetitive and unpleasant
Acknowledged as excessive or unreasonable
Patient tries to resist, but at least one obsession/compulsion is unsuccessfully resisted
When do obsessional/compulsion disorder usually begin?
adolescence or early adulthood
Outline the pathophysiology of OCD
Re-entry circuits in basal ganglia = high activity makes it hard to get rid of excess
Reduced serotonin
Reduced activity in dorsolateral prefrontal cortex, orbitofrontal cortex, cingulate cortex
PANDAS = Paediatric Autoimmune Neuropsychiatric Disorder Associated with Streptococcal Infection
What are the basal ganglia re-entry circuits?
Normal = INPUT from sub/cortical areas, PROCESSING by caudate nucleus and putamen, OUTPUT by inhib projection from GP and SN to thalamus
OCD = circuit loop from output back to processing that continues around
What is Paediatric Autoimmune Neuropsychiatric Disorder Associated with Streptococcal Infection?
Sudden onset of OCD post infection with group-A beta-haemolytic strep
Antibodies ‘cross-react’ with neurones in basal ganglia, causing symptoms
How is OCD treated?
CBT
Exposure response prevention = not allowing you to carry out your compulsion, breaking the cycle
High dose SSRIs
Antipsychotics
Clomipramine – don’t tend to use due to side effects
Deep brain stimulation – stimulate STN to stim GPi to inhibit thalamus – less stim to the cortex
What is post traumatic stress disorder?
Repetitive, intrusive recollection or re-enactment of the event in memories, daytime imagery, or dreams
Conspicuous emotional detachment, numbing of feeling, and avoidance of stimuli that might arouse recollection of the trauma
Outline the pathophysiology of PTSD
Hyperactivity of amygdala, causing exaggerated response to perceived threat
Lower cortisol = lower inhibition of traumatic memory retrieval and sympathetic response
How is PTSD treated?
SSRIs
CBT
Eye Movement Desensitisation Reprocessing (EMDR) – follow visual stimulus while recounting past events
