CM: Depressive Disorders Flashcards
What is the noradrenergic hypothesis of depressive disorders?
depression secondary to low NE - problematic for several reasons (number and timing)
What is the serotonergic hypothesis of depressive disorders?
depression due to CNS seretonin deficit - but further studies showed conflicting results of different seretonin levels in depressed people
What is the HPA axis hypothesis of depressive disorders?
stress releases cortisol via HPA axis
excessive activation and hypercortisolemia can damage hippocampal neurons by decreased dendritic arborization and inhibiting neurogenesis - observed in half of depressed pts, dexamethasone suppression fails
What is the animal study evidence for the HPA axis hypothesis of depressive disorders?
“socially defeated mice” have HPA axis abnormality
rodents and humans - HPA axis and cortisol abnormalities can be corrected w antidepressants
What is the kindling hypothesis of depressive disorders?
repeated exposure to stress leads to sensitization of limbic system - further stresses lead to progressive sensitization and permanent physiologic changes
What is the evidence for the kindling hypothesis of depressive disorders?
correlation b/w trauma in early life and later depression
in ppl w recurrent depression stress threshold for depressive episode is lower
What is the neurotrophic hypothesis of depressive disorders?
def of neurotrophic support may contribute to hippocampal pathology of depression reversal of def by antidepressants may contribute to resolution of depressive symptoms BDNF = chronic stress decreases levels in rodents, chronic admin of antidepressants increases levels (could explain delayed response to antidepressants in humans)
What is the role of glutamate and ketamine in depressive disorders?
ketamine blocks glutamate at NMDA receptor - rapid hippocampal neurogenesis in rodents, reversal of stressed depressive behaviors
in humans - one dose has produced antidepressant effects, but only lasts hours (also watch for hallucinations!)
What is the definition of major depressive disorder?
one or more major depressive episodes
no history of manic or hypomanic episodes
single episode or recurrent
mild, moderate, or severe (hospitalize)
What is a major depressive episode?
syndrome w at least 5 depressive symptoms lasting at least 2 weeks
What is the SIGECAPS mnemonic for the symptoms of depression?
S leep I nterests G uilt/worthlessness E nergy C oncentration/indecisiveness A ppetite P sychomotor S uicide \+ depressed mood or decreased pleasure
To be considered a psychiatric disorder, what must a depressive episode do?
cause impairment
must not be substance/med induced, due to another med condition, or better accounted for by another mental disorder = “rule-outs”
What is persistent depressive disorder (dysthymia)?
depressed mood lasting at least 2 yrs and including at least 2 depressive symptoms = chronic depression
can have both this and MDD
excludes manic or hypomanic episodes, usual rule-outs apply
What is premenstrual dysphoric disorder?
at least 5 depressive symptoms in final week before menses onset, improve with onset, become minimal or absent in week after
= depressive symptoms + physical manifestations
What are “other specified depressive disorders”?
disorders w depressive features that don’t meet criteria for MDD, persistent, or premenstrual dysphoric disorder
