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

Chronically elevated cortisol suppresses hippocampal neurogenesis in the dentate gyrus and causes dendritic retraction, leading to the volume reduction observed in imaging studies of PDD.

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

The monoamine hypothesis proposes that reduced availability or functional activity of serotonin, norepinephrine, and dopamine underlies depressive symptoms, and remains a foundational (though incomplete) model for PDD.

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 rhythm disruptions in PDD affect the temporal coordination of cortisol, melatonin, and monoaminergic systems, contributing to the chronic mood instability and neurovegetative symptoms.

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

Early and chronic stress-induced methylation of the NR3C1 glucocorticoid receptor gene reduces receptor expression in the brain, impairing cortisol feedback inhibition and maintaining HPA axis hyperreactivity.

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

Altered gut microbiome composition (dysbiosis) in PDD can influence the CNS via the vagus nerve, immune activation, and production of neuroactive metabolites like short-chain fatty acids and tryptophan derivatives.

Persistent Depressive Disorder Practice Test

Persistent Depressive Disorder Practice Test

Persistent Depressive Disorder Persistent Depressive Disorder Neurobiology & Etiology 3