6- Depression Flashcards
What type of disorder is depression?
A common and serious mood disorder
3 main symptoms associated with depression
- Persistent feelings of sadness and hopelessness
- Anhedonia
- Physical symptoms
What is anhedonia?
Loss of interest in activities once enjoyed
How are physical symptoms also referred to?
Somatic symptoms
What key function is often affected in depression?
Sleep
How is depression diagnosed by the DSM-5?
Someone must be experiencing significant symptoms for at least 2 weeks, and these must include a depressed mood and/or loss of interest/pleasure
3 other symptoms associated with depression
- Feelings of worthlessness or excessive guilt
- Diminished ability to think/concentrate
- Fatigue
What must symptoms cause the individual for a DSM-5 depression diagnosis?
Clinically significant distress or impairment in social, occupational, or other areas of functioning that are important
What must symptoms not be for a DSM-5 depression symptoms?
Must not be a result of substance abuse or another medical condition
What is the lifetime prevalence of depression?
15-20%
What is 12-month depression prevalence?
About 7%
How much is prevalence increased among those between 18-29 than among those aged 60+?
3 times higher
How much higher are prevalence rates for women than men?
About 1.5-3 times higher
What is the recent trends in depression prevalence?
Increasing
What is major depressive disorder associated with?
High mortality
How is the HPA axis activated?
By a physical or emotional stressor
How is the HPA axis thought to be affected in depression?
Less well-regulated
How do cortisol levels appear to be in depression?
Increased and not regulated normally
Why is more cortisol released from adrenal glands in depression?
Caused by more release of adrenocorticotropin hormone from the pituitary gland due to the hypothalamus secreting higher levels of corticotropin-releasing factor
What do MRI studies show in patients with depression?
Reduced hippocampal volume
What does the hippocampus have a high number of?
Cortisol receptors
What is persistently elevated cortisol levels thought to lead to?
Hippocampal damage
Why does hippocampal damage further impair cortisol feedback and regulation?
As the hippocampus function is to regulate and inhibit the HPA axis
What may longer durations of untreated depressive episodes correlate with?
Reductions in hippocampal volume
What could hippocampal damage also explain in depression?
Why memory and other cognitive functions are impaired in depression
What does anhedonia suggest?
A dysregulation in reward processing
Where is the brain’s reward circuit?
Mesolimbic dopamine circuit
What is seen in the reward circuit in major depressive disorder?
‘Blunted’ activity
What can the pattern in the reward circuit predict in depression?
Which individuals go on to have a depressive episode
What last-resort treatment alleviates symptoms among patients who don’t respond to drug treatments?
Deep brain stimulation of the Nucleus Accumbens
What neurotransmitter system play a role in regulating many depression functions?
Serotonin
Where are reduced serotonin receptors seen in depressed patients?
In the frontal cortex and hippocampal regions
What are the most commonly prescribed medications to treat depression?
SSRIs
How do SSRIs work?
By inhibiting serotonin reuptake and increasing serotonin levels
What is the effect of serotonin transporters (SERT) being inhibited?
These transporters recycle serotonin back into the presynaptic terminal causing an increased amount of serotonin to remain in the synaptic cleft and stimulating the postsynaptic receptors for a more extended period
How does increasing serotonin activity alleviate depression symptoms?
Improves patients’ mood and energy levels
What extra effect do SSRIs have?
Thought to protect and regenerate the hippocampus
What does SSRI treatment do in the hippocampus?
Stimulate growth of new neurons (neurogenesis)
What can explain why SSRIs take up to 1 month for a full effect?
Neurogenesis takes many weeks
How is depression defined?
An extended period of depressed mood and/or anhedonia
What does HPA axis dysregulation lead to?
Persistently elevated cortisol levels that cause hippocampal damage
What could explain anhedonia?
Blunted response within the reward circuit
What is the main depression treatment?
With SSRIs
What is the effect of SSRIs?
Compensate for serotonin system dysregulation and also help repair the hippocampus
