Persistent Depressive Disorder Persistent Depressive Disorder Neurobiology & Etiology 3

Question 1

How does chronic elevation of glucocorticoids contribute to hippocampal volume reduction in persistent depressive disorder?

Accepted Answer

By suppressing neurogenesis and inducing dendritic atrophy via glucocorticoid receptor signaling

Answer

By triggering autoimmune destruction of hippocampal tissue

Answer

By blocking blood flow to the hippocampus

Answer

By directly depleting serotonin stores in hippocampal synapses

Question 2

What is the most accurate description of the monoamine hypothesis as it applies to persistent depressive disorder?

Accepted Answer

Deficiencies in serotonin, norepinephrine, and/or dopamine contribute to depressive symptomatology

Answer

Excess monoamines drive the chronicity of depressive symptoms

Answer

The monoamine hypothesis only explains acute MDD, not chronic forms like PDD

Answer

The hypothesis has been disproven and fully replaced by inflammatory models

Question 3

What does research on circadian rhythm disruption suggest about the etiology of persistent depressive disorder?

Accepted Answer

Disrupted circadian rhythms impair mood regulation by dysregulating melatonin, cortisol, and neurotransmitter cycling

Answer

Circadian disruptions only impair sleep quality without directly affecting mood

Answer

Circadian abnormalities are a consequence but never a cause of depressive pathology

Answer

Only seasonal affective disorder involves circadian rhythm dysregulation

Question 4

Which epigenetic finding best explains the long-term persistence of stress sensitivity in persistent depressive disorder?

Accepted Answer

Stress-induced methylation changes at glucocorticoid receptor gene (NR3C1) promoters that persist long-term

Answer

Permanent deletion of mood-regulating genes caused by oxidative stress

Answer

Epigenetic changes in PDD are transient and reverse within weeks of symptom remission

Answer

DNA methylation changes only occur during fetal development and cannot be induced by adult-life stress

Question 5

What does research on the gut-brain axis suggest about its contribution to persistent depressive disorder?

Accepted Answer

Dysbiosis in gut microbiota may influence depressive symptoms through vagal nerve signaling and neuroinflammatory pathways

Answer

Gut microbiome composition has no established influence on mood disorders

Answer

The gut-brain axis affects only anxiety disorders, not depressive conditions

Answer

Probiotic supplementation is currently the most effective treatment for persistent depressive disorder

Question 6

Which neuroimaging method most effectively demonstrates reduced functional activity in prefrontal regions of patients with persistent depressive disorder?

Accepted Answer

Functional MRI (fMRI) and positron emission tomography (PET)

Answer

Structural MRI measuring cortical thickness

Answer

CT scan with contrast enhancement

Answer

Diffusion tensor imaging (DTI) measuring white matter integrity

Question 7

How does norepinephrine dysfunction contribute specifically to the cognitive symptoms of persistent depressive disorder?

Accepted Answer

Reduced norepinephrine transmission in prefrontal circuits impairs working memory, attention, and executive function

Answer

Norepinephrine excess causes hyperarousal that disrupts concentration

Answer

Norepinephrine dysfunction primarily affects vegetative symptoms but not cognition in PDD

Answer

Norepinephrine interacts only with limbic structures and has no role in cognition