Depression

Question 1

what is psychiatry

Answer 1

branch of medicine which focuses on the prevention, assessment, and treatment of mental, emotional and behavioural disorders

Question 2

what is delusion?

Answer 2

a belief that is clearly false and indicates an abnormality in content of thought, the belief is held despite being presented with evidence against it

Question 3

what is hallucination?

Answer 3

a sensory preception in the absence of a corresponding external or somatic stimulus and described according to the sensory domain in which it occurs

Question 4

what is psychosis

Answer 4

hallcination, delusion OR hallucination and deluision
- loss of contact with external reality

Question 5

what is the central component of psychosis

Answer 5

impaired reality testing

Question 6

what is delirium

Answer 6

acute, fluctuating change in attention and consciousness including disorganized thoughts

Question 7

what is a depressive episode

Answer 7

experience of low or depressed mood, loss of interest in most activities

Question 8

what are the characteristics of someone with mania

Answer 8

increased talkativeness, rapid speech, decreased need for sleep, racing thoughts, distractibility, increase in goal-direct activity, elevated mood, impulsivity, irritability

Question 9

what is the duration of mania?

Answer 9

1 week or more Or if severity of symptoms warrants hospitalization

Question 10

how long is hypomania

Answer 10

at least 4 days, shorter than mania

Question 11

hypomania does not cause what?

Answer 11

does not cause major deficit in social or occupational functioning

Question 12

what are the two components that must be present in the DSM-5 for Major Depressive Disorders

Answer 12

• depressed mood
• anhedonia

Question 13

what is anhedonia?

Answer 13

loss of interest/pleasure in almost all activities

Question 14

what are the leading biomedical theories for MDD

Answer 14

• monoamine hypothesis
• stress-induced depression hypothesis
• neurotrophic/neuroplasticity hypothesis
• cytokine hypothesis/neuroinflammation hypothesis
• circadian hypothesis of depression
• GABA-glutamate-mediated depression hypothesis

Question 15

what is the monoamine hypothesis?

Answer 15

altered levels of monoamine neurotransmitters,, specifically serotonin, noradrenaline, and dopamine cause depression

Question 16

what is the critique for the monoamine hypothesis?

Answer 16

critiqued in that abruptly decreasing serotonin and/or dopamine doesn’t cause depression in a healthy person

Question 17

what is stress-induced depression hypothesis

Answer 17

chronic stress leads to dysregulation of the hypothalamic-pituitary-adrenal (HPA) axis

Question 18

what does chronic HPA activation lead to?

Answer 18

excess cortisol secretion and pro-inflammatory agents that damage glia and neurons, interfere with neurogenesis and reduce glutamate and GABA

Question 19

what is the critique for stress-induced depression hypothesis

Answer 19

hypercortisolism is not a feature of all MDD cases AND not clear what causes HPA dysregulation (i.e. loss of GR sensitivity)

Question 20

explain the neurotrophic and neuroplasticity hypothesis for depression

Answer 20

Brain-derived neurotrophic factor (BDNF) promotes neurogenesis, regulates differentiation and growth of neurons
Decreased BDNF gene expression, decreased BDNF levels and receptors in MDD patients
Increased cortisol can inhibit BDNF
Same triggers that elevated cortisol appear to block neurogenesis

Question 21

what do antidepressants do?

Answer 21

have been demonstrated to stimulate neurogenesis in adult hippocampus (animal studies)

Question 22

explain cytokine and neuroinflammation hypothesis for depression

Answer 22

MDD patients have increased levels of pro-inflammatory markers and increased levels of macrophage/monocyte activation

Question 23

explain the circadian physiology in a healthy state

Answer 23

• light inhibits pineal gland from producing melatonin by activating neurons with suprachiasmatic nucleus of the hypothalamus
• SCN regulates production of melatonin throughout the body
• melatonin production increases at night during conditions of dark

Question 24

explain the circadian hypothesis for depression

Answer 24

genes controlling circadian rhythms in anterior cingulate cortex are dysregulated in depression
- phase advance in cortisol rhythm and reduced amount of melatonin production seen in some patients with MDD

Question 25

explain the excitatory neurotransmitters hypothesis for depression

Answer 25

• Glutamate may cause excitotoxicity resulting in neuronal atrophy and reduced synaptic connectivity
  ○ Stress induced changes may be accelerated in the presence of elevated Glu
  ○ Reduced GABA in CSF of MDD px – may be d/t change in serotonin which modulates GABA, which in turn modulates glutamate

Question 26

explain glutamate excitotoxicity for depression

Answer 26

excessive accumulation of glutamate within synaptic cleft results in over stimulation of postsynaptic glutamate receptors
- Via NMDA receptor glutamate promotes calcium influx

Question 27

describe bipolar 1

Answer 27

At least 1 manic episode and usually depressive episodes

Question 28

describe bipolar 2

Answer 28

Major depressive episodes with at least 1 hypomanic episode

Question 29

what are the pathophysiology of bipolar disorders

Answer 29

• Circadian Rhythm Dysfunction
• Metabolic Dysfunction
• Mitochondria Dysfunction
• Glutamate Excitotoxicity

Question 30

explain the aspect of circadian rhythm dysfunction for bipolar disorder

Answer 30

• During mania there is a reduced need for sleep
• Observations in patients with bipolar disorders:
  ○ Changes in melatonin levels
  ○ Changes in melatonin receptor expression with CNS
  ○ Changes in cortisol profiles (patterns of release)
  ○ Sleep deprivation as well as light therapy have been effective as adjunct in some cases of bipolar disorder

Question 31

explain the aspect of metabolic dysfunction for bipolar disorder

Answer 31

• Various metabolic abnormalities have been found in patients with bipolar disorder such as:
  ○ Increased risk of obesity, type 2 diabetes, and reduced longevity due to increased cardiovascular problems
  ○ Increased amount of leptin secreted in obese patients with bipolar compared to obesity alone
  § Leptin regulated appetite AND sleep duration
• A hypothesis suggests that the body is forced to compensate for the high metabolic demand of the brain during manic states:
  ○ Reduced appetite
  ○ Reduced sleep
  ○ Increased energy expenditure

Question 32

explain the aspect of mitochondria dysfunction for bipolar disorder

Answer 32

Impairment in mitochondrial function resulting brain metabolism shifting towards glycolysis
- Polymorphisms within mitochondrial DNA linked to BD
- Reduced levels of phosphocreatine within frontal cortex
- Evidence of impaired oxidative phosphorylation
- Reduced expression of genes coding for various complexes of the electron transport chain in hippocampus

Question 33

explain the aspect of glutamate excitotoxicity for bipolar disorder

Answer 33

increased glutamate in frontal cortex of px with BD
- increased levels of excitatory glutamate appear to result an increased energy demand on the neuron,
increased glucose consumption in areas of high glutamate synaptic activity