Science of Depression

Question 1

3 main symptoms of depression

Answer 1

Low mood, anhedonia (not taking pleasure in things), low energy

Question 2

“Biological symptoms”

Answer 2

Poor sleep
Poor appetite
Reduced libido
Poor concentration

Question 3

“Cognitive symptoms”

Answer 3

Worthlessness (low self esteem)
Guilt
Hopelessness
Suicidal thoughts

Question 4

The HPA axis

Answer 4

Hypothalamus release CRH in response to stressful experiences.

Causes anterior pituitary to release ACTH

In blood reach adrenal cortex with releases CORT

(negative feedback loop)

Question 5

How those with depression differ

Answer 5

Increased CRH
Enlarged adrenals and pituitary
Reduced negative feedback
Reduced GR expression in the brain (“glucocorticoid resistance”)

Question 6

What factors contribute to high glucocorticoid expression?

Answer 6

Care as baby
Role of serotonin
Possibly oxytocin mediated

Question 7

Steroids

Answer 7

Neurotoxic
Cause neuro-vulnerability
Affect dendrite formation
Reduces neurogenesis
Cause changes to the EEG - particularly frontal lobes and hippocampus

Question 8

Medial Pre Frontal Cortex (frontal lobe)

Answer 8

Evaluating emotional state
Social cognition
Less volume loss in response to stress / depression

Question 9

Dorsolateral PFC (in frontal lobe)

Answer 9

Working memory
Problem solving
Large volume loss in response to stress / depression

Question 10

Hippocampus

Answer 10

Important for memory
Reduces in size with stress / depression
Much of the volume loss is irreversible

(Is depression a neurodegenerative disease?)

Question 11

Neurogenesis

Answer 11

Growth of axons and dendrites

Stress down regulates neurogenesis

Stress also affects dendrites via reducing BDNF (brain derived neurotrophic factor) - linked with suicidal thoughts

Question 12

How do antidepressants work?

Answer 12

Affecting gene expression

Increase GR expression
Increase neurogenesis
Increase BDNF synthesis

Takes time.

Question 13

Medically Diagnosed Depression (MDD) is a neurogenerative disease of

Answer 13

impaired plasticity

Question 14

Psychodelics?

Answer 14

Reduced activity in the DMN (default mode network)
Reduced alpha power in PCC

Question 15

Brain attempts to reduce entropy

Answer 15

The brain tried to reduce surprise so is make predictions.
This is top-down processing
Initially visual predictions, eventually words, concepts and core beliefs.

Question 16

Meditiation

Answer 16

Reduces activity in the DMN
treats and prevents MDD
Increases attention to breath
Being more aware of one’s own mind

Question 17

Depression is a disease of reduced p_____ and a disease of increased s____-r_____ thinking.

Answer 17

plasticity

self-referential