Depression (Affective Disorder)

Question 1

Prevalence

Answer 1

7.2% of 18+ year olds in US

Question 2

Heritability

Answer 2

Monozygotic twins 69% concordance rate
Dizygotic twins 13% concordance rate
Genes involved in controlling circadian rhythms and that control glutamate are implicated

Question 3

Norepinephrine and serotonin (monoamine hypothesis)

Answer 3

Support: depression can be treated with MAO inhibitors or drugs that inhibit reuptake of monoamines
Against: decrease serotonin in those without personal or family history of depression does not lead to depression, SSRIs and SNRIs increase serotonin/norepinephrine very quickly, but drugs take weeks before effects, its too simple

Question 4

Prefrontal cortex

Answer 4

Stress can play a role
Observational evidence: reduced activity in the frontal lobe after several kinds of treatments compared to placebo

Question 5

Neurogenesis and exercise

Answer 5

Hippocampus is one area of the adult brain capable of neurogenesis
Stressful experiences reduce neurogenesis
Several antidepressants increase neurogenesis

Question 6

Sleep and depression

Answer 6

Major depression: fatigue, changes in sleep, reduced sleep latency, reduced REM latency, reduction in slow-wave sleep, increased sleep fragmentation