Exam 4: Affective Disorders Pt 2 Flashcards
characteristics of depression- circadian rhythms
altered in depressed individuals
-these are controlled by the molecular biological clock in the suprachiasmatic nucleus of the hypothalamus
what systems do circadian rhythms control
NE, 5-HT, DA systems - may be the basis for mood dysfunction
depression and circadian rhythms
abnormal circadian rhythm in cortisol secretion
many depressed people fail to respond to ____
dexamethasone
dexamethasone
a synthetic glucocorticoid that should act as a negative feedback to suppress release of CRF and ACTH resulting in lower cortisol levels
the most consistent neuroendocrine abnormality in depressed individuals is an abnormal secretion of
cortisol
-many depressed patients have elevated cortisol levels in response to greater than normal release of ACTH and CRF
-hypersecretion most likely due to abnormal regulation of CRF by hypothalamus
early life traumas alter the set point for what
the HPA axis
- becomes permanently over responsive
- inc risk for depression, anxiety disorders, alcohol abuse
Sleep changes in MDD
-altered sleep is most common and persistent symptom
-onset of sleep is delayed
onset of REM sleep occurs earlier
dec i slow wave or deep sleep with repeated awakenings during the night
sleep changes in bipolar disorder
during depressive episodes: sleep resembles unipolar depression
during mania sleep is greatly reduced or absent with no loss of energy
-when manic patients are treated with a sleep inducing benzo manic symptoms subside
PET scans of blood flow in depressed patients show inc activity where
orbitofrontal cortex and amygdala
inc metabolic activity in amygdala correlated with
severity of depression and returns to normal after antidepressant drug treatment
corticolimbic changes in MDD amygdala and ACC
amygdala: at rest and in response to danger
ACC: emotional conflict-should I be happy or sad about this
corticolimbic changes in MDD
hyperactivity in dorsomedial PFC
dmPFC: judgement and decision making-tells amygdala we are fine
weakened connectivity between dmPFC and amygdala in depressed individuals
-failure to properly regulate amygdala response in depressed individuals
insula in MDD
hyperactive, more aware of body states, inc HR bc nervous, pit in stomach
thalamus (PVN) in MDD
visual relay of thalamus activated when viewing emotional faces
-good at picking up on emotions of others - why they think so many people upset with them