Affective Disorders Part 1 Flashcards
- Deck is about the prevalence and risk factors of bipolar disorder, MDD, and structural changes that occur as well as touching on use of antidepressants and genetic factors
What are the cardinal symptoms of a low mood?
(3 marks)
Decreased interest in activies once enjoyed - anhedonia
Lack of energy - anergia
Depressed mood - invariant
What are the cognitive symptoms of depression?
(5 marks)
Reduced concentration and memory
Poor self esteem
Guilt
Helplessness
Suicide and self-harm
What are somatic symptoms of depression?
(3 marks)
Sleep less
Weight loss
Psychomotor retardation
What is hypomania/ mania?
Feeling high/ euphoric as a deviant from normal behaviour by known observer
Which is more prevalent in society - bipolar disorder or depression?
Depression
What are some physiological effects caused by bipolar disorder?
(2 marks)
Endogenous hormone fluctations e.g. thryroid, menstrual dysfunction
Why is bipolar disorder proposed to be a disconnection syndrome?
In ventral striatum some patients in their depressive state show less activity in the ventral striatum
What is dopamine dysregulation syndrome?
Dysfunction of the reward system observed in individuals taking dopaminergic medication for an extended length of time
How have GWAS helped with identifying MDD?
(1 mark)
By indentifying polymorphisms that may indicate MDD (haven’t foudn any FOR sho yet)
How many loci were indentified with ebing associated with MDD?
44 loci
What are some of the functional changes in MDD?
(3 marks)
- Decrease in reward processing and pleasure
- Hedonic response - pleasure reward decrease
- Decrease in reward experience
What does the medial prefrontal cortex do (mPFC)?
Serves in distinct aspects of workign memory and executive control
What anatomical changes occur in MDD in regard to the NAc, amygdala and mPFC?
(3 marks)
The NAc decreases in volume and activity - the amygdala increases in volume. The mPFC decreases in volume and activity - HOWEVER IT IS UNKOWN WHETHER THIS IS A CONSEQUENCE OF THE DISORDER OR AN ONSET TO IT
What chemical test is used to measure stress levels in animals after chronic exposure to mild physical stressor?
(2 marks)
- Sucrose prefernce test - normally an animal would prefer the sucrose water but is animal has udergone stress will consume less
- Measure how much animal consumes and whether it is within range of ‘too little’ which may show animal is depressed
What is the forced swim test?
Animal is forced to swim in small container until it gives up - signs of depression antidepressed animal will try harder for longer
What does the foot shock test show?
(2 marks)
Learned helplessness test - after a few shocks animal will start to give up and just accept the shocks - signs of depression
What is the chronic social defeat stress test and what does it show?
(3 marks)
- Put mouse with an ggressor that causes animal stress
- Animals may consume less sucrose indication of depression
- Animal won’t stay in corners or fight - symptom of depression
How does stress affect the PFC and hippocampus and what is this associated with?
(2 marks)
- Causes progressive atrophy in PFC and hippocampus - associated with reduction of markers of glutamatergic and inhibitory markers (GAD67)
What structural abnormality can be seen after chronic immobilisation of stress to the amygdala?
(1 mark)
- Enhanced branching/ increase in spine formation and hypertrophy
What ‘tool’ is used to detect light in animals in optogenetics?
- Microbial opsins - able to change ion flow
What is a consequence of dopamine deficieny in depression?
Reduced DAT transporters in those with anhedonia
Outline the monoamine hypothesis.
(2 marks)
- States that the underlying pathophysiological basis of depression is a depletion in the levels of serotonin, norepinephrine, and or dopamine
What is functional connectivity?
(2 marks)
The temporal coincidence of spatially distant neurophysiological events. Measures the correlation of brain activity between 2 or more active regions in the brain
What is BP characterised by?
Dysfunction in the fronto-limbic neural circuit
In BP disorder where can an increase of activity be seen in emotional processing?
Limbic structures
Where is there reduced functional connectivity in BP disorder?
- Ventral striatum with decreased connectivity strength
What does the orbitomedial prefrontal cortex do?
Represents reward value for goals of action
Give an example of genetic polymorphisms that have been asscociated with depression.
(2 marks)
MTHFR and ApoE
Which allele carriers are likely to develop depressive symptoms or MDD after childhood trauma?
T-allele carriers
How does the metabolism of folate by MTHFR contribute to the developement of MDD?
(3 marks)
- MHTFR metabolises folate and makes a methyl donor for sysnthesis of methionine from homoscyteine
- Folate causes synthesis of serotonin and other NTs - decreasing homocysteine levels to have an excitotic effect via Ca2+ glutamate receptors
- \Folate is needed for biosynthesis of antidepressants - so less folate less senstivity to antidepressants
