the science of depression Flashcards
1
Q
biological symptoms of depression
A
- Poor sleep
- Poor appetite
- Reduced libido
- Poor concentration
2
Q
cognitive symptoms of depression
A
- Worthlessness (poor self esteem)
- Guilt
- Hopelessness
- Suicidal thoughts
3
Q
stress vulnerability model
A
- Our ‘vunerability’ can be genetic, or a result of early/prenatal experience
- Early experience sets our neuroendocrinological thermostat-epigenetics
4
Q
the HPA axis and depression
A
- Increased CRH (corticotropin-releasing hormone)
- Enlarged adrenals and pituitary
- Reduced -ve feedback
- Reduced GR (glucocorticoid receptor) ‘glucocorticoid resistance’
5
Q
role of early adversity and parenting
A
- History of childhood maltreatment (with or without current MDD) -> ↑ACTH release in response to stress
- Offspring of “high licking” lab rats show high GR expression (higher ACTH suppression)
6
Q
social rank affecting HPA function
A
Subordinate monkeys have:
• Heavier adrenal glands.
• Increased cortisol in hair
• Reduced dexamethasone suppression
7
Q
how does stress affect the brain?
A
- Neurotoxic
- Cause neuro-vulnerability
- Affect dendrite formation
- Reduces neurogenesis
- Cause changes to the EEG.
- Particularly affects the frontal lobes and hippocampus.
8
Q
frontal lobe role on emotion
A
Medial PFC: • Evaluating emotional state • Social cognition • Less volume loss Dorsolateral PFC: • Working memory • Problem solving • Large volume loss
9
Q
the hippocampus role on emotion
A
- Reduced in size in MDD
- Dose related effect – correlated with number of and length of episodes
- Associates with learning based cognitive deficits
- Much of the volume loss is irreversible
10
Q
neurogenesis
A
- Grow axons and dendrites, and integrate into existing networks
- 6% of the total dendate gyrus population a month
- Restraint and shock stress causes reduced neurogenesis
11
Q
effect of stress on dendrites
A
- Mediated by reduced neurotrophins e.g. Brain derived neurotrophic factor (BDNF)
- Stress -> ↓BDNF (animals) - Reversed with antidepressants
- Low BDNF in unmedicated depressives - Normal to high in medicated patients
- The lowest levels in post-mortems of successful suicide victims.
12
Q
how do antidepressants work?
A
- Antidepressants increase GR expression (regulating HPA activity)
- Antidepressants increase neurogenesis
- They increase BDNF synthesis. ∴ improve connectivity and increase number of synapses
13
Q
freud model
A
super-ego (morals/rules) vs Id (needs wishes)
14
Q
modern scanning techniques
A
- Based on oxygen or glucose take up.
- Much improved from “if it light up it’s active”
- Functional connectivity (from the mid 90s) Functional connectivity- Spatially distinct areas of the brain showing similar activity at similar times
- Allows the study of networks.
15
Q
default mode network
A
• It’s what comes on when there’s nothing to do (“resting state”) Autobiographical details • The self’s place in time and space • Projecting to other places in time and space Self reference • Referring to traits or states • Emotional and moral reasoning Thinking about others • Theory of mind • Social judgements/evaluations
