Depression

Question 1

Genes

Answer 1

Heritability
Risk-genes
gene environment interactions

Question 2

Diagnostics

Answer 2

Depression or irritable mood
Decreased interest in pleasurable activities
Significant weight gain or loss
Insomnia or hypersomnia
Fatigue or loss of energy
Feelings of worthlessness or excessive guilt
Diminished ability to think or concentrate
Recurrent thoughts of death or suicide

Question 3

Diagnosis

Answer 3

10-20% experience depression
Twice as such females
co-morbidity with anxiety, ADHD, addiction

Question 4

Lifestyle disease?

Answer 4

Diseases that appear to increase in frequency as people live longer

No not related to demographic variables

Question 5

Brain circuits

Answer 5

Depression symptoms are linked to malfunctioning brain circuits
Genes+environmental risk factors produce inefficient information processing in neuronal circuitry

Question 6

Etiology current ideas

Answer 6

Overactive amygdala
Decreased activity PFC
Decreased hippocampal volume: neurogenic hypothesis
Overactive HPA-axis
Decreased levels BDNF: BDNF hypothesis

All connected in complex interactions

Question 7

DL-PFC and the amygdala

Answer 7

DL-PFC helps with decision memory and working memory. It helps regulate emotions when completing tasks in the amygdala. Those with emotional depression have disrupted communicatin with the amygdala and DL-PFC leading to overreactions and emotional responses when doing tasks.

Question 8

Hippocampal volume

Answer 8

Some studies found reduced hippocampal volume in patients with MDD, others did not

Possible explanations contradictory results:

Dependent upon subtype of depression

Reduced hippocampal volume when depressed / normal hippocampal volume when successfully treated or non-depressed

Reduced hippocampal volume indicator for vulnerability depression in healthy people

Question 9

Reduction in volume PFC and hippocampus

Answer 9

Loss of volume neurons: : dendritic atrophy and spine loss, decreased neuronal synapses

2. Loss of number neurons: inhibition neurogenesis (in hippocampus)

High sustained levels of cortisol causes both

Question 10

Cortisol

Answer 10

Inhibits gene expressed of brain deprived neurotrophic factor
High cortisol > toxic for hippocampal neurons: dendritic atrophy and spine loss, decreased neuronal synapses

Inhibition of birth new granule cells in hippocampus = decreased neurogenesis

Question 11

HPA-axis

Answer 11

WHY would in individual’s HPA-axis be overactive?

Combination of genetic, epigenetic, and environmental factors may affect regulation of the HPA axis

Genetic: variations in gene-variants for proteins that build HPA-axis

Epigenetic & environmental: early experiences, stress during pregnancy, stress during post-natal life, poor parental care, childhood abuse, can affect the glucocorticoid system in the hippocampus and HPA-axis well into adulthood (altered gene regulation of brain cortisol receptor gene; via epigenetic OR other pathways)

Question 12

Ketamine

Answer 12

Dissociative anesthetic ketamine, an NMDA-antagonist, produces rapid (within hours!) antidepressant responses in treatment resistant patients

Effect lasts 1-2 weeks

Ketamine rapidly induces synaptogenesis, neurogenesis and reversal of atrophy caused by chronic stress

Question 13

Genetic factors

Answer 13

Heritability:

MDD > relatively low heritability

Less severe depression: 25%

Severe depression: 50%

Bipolar depression (manic depression): 80%