Neurobiology of Mood Disorders Flashcards
How could depression be explained?
Altered sensitivity/accuracy of brain systems evaluating rewards and cues predicting reward within the environment
How could anxiety be explained?
Altered sensitivity/accuracy of brain systems evaluating threat and cues predicting threat within the environment
What is the M:F ratio in depression?
1:2
What is the heritability of major depression?
70% (shared with anxiety)
What is the increased risk in 1st degree relatives where proband has MDD or BPD?
MDD: 3x
BDP: 2x
Does childbirth cause hormonal changes which lead to low mood?
No association ever shown
How many women experience ‘blues’ within 2 weeks of childbirth?
75%
What is the sex ratio of Bipolar disorder?
1:1
What changes in the HPA axis (cortisol) occur in major depression?
Increased ACTH secretion Increased CORT secretion Elevated CORT in urine, saliva Increased CRH in CSF Blunted ACTH to CRH Enlarged adrenals 50-70% fail to suppress CORT production following DEX Chronic hypersecretion of CRF in hypothalamus
What changes in the HPT axis (T3 and T4) occur in major depression?
20-30% MD populations show some dysfunction
Increased TRH in CSF
TSH response to TRH blunted in 20-25% despite normal basal TSH, T3 and T4
Chronic hypersecretion of TRH in hypothalamus
What are the key regions implicated in mood disorders?
Orbital prefrontal cortex and ventromedial prefrontal cortex
Dorsolateral prefrontal cortex
Hippocampus and amygdala
Anterior cingulate cortex
What have been proposed as the limbic motor and sensory cortices that engender the feeling and motivation associated with emotion?
Anterior Cingulate Cortex and Anterior Insular Cortex respectively
What is seen in structural imaging of BPD?
Reduced grey matter volume in BA 24 (anterior cingulate)
What is seen in functional neuroimaging of BPD?
Increased metabolism in amygdala, correlates with outcoe.
What is seen in post mortem studies of BPD?
Reduced glial cell numbers with normal neuronal numbers in BA24 and olfactory cortex
