depresia

Question 1

what is depression

Answer 1

persistent feeling of severe despondency and dejection

Question 2

What are the 3 main elements according to the DSM 5

Answer 2

A. 5 or more symptoms present for at least a 2 week period
Symptoms result in a significant change from previous functioning
Include at least 1 of: depressed mood or loss of interest of pleasure

b. cause clinical significant distress or impairment in social, occupational or other functioning

c. should mot be direct physiological effect of a substance or a general medical condition

Question 3

what are the major symptoms of depression

Answer 3

depressed mood most of the time - something that is obvious both to the person and others who are close to the patient

diminished interest or pleasure in vast majority of activities the person was engaged with

loss or gain in weight

changes in quality and quantity of sleep

motor changes - agitation

fatigue

feelings of wrothlessness or inappropriate guild

diminshed ability to concentrate

reccurent thorughts of death

Question 4

what is the prevalence of depression

Answer 4

lifetime - chance of having depression at some point in life: 6-25%

high income countries have higher rate of depressed patients

annual prevalence - about 4%

more present in females

Question 5

why might high income countries have higher prevalance

Answer 5

poor countries may lack infrastructure to collect data on depression, and are less likely to recognise it as an illness

Question 6

what are the causes of depression

Answer 6

biological
- NT
- brain, vascular damage

genetic
-family studies
-twin studies

environmental

Question 7

What is the role of NT in depression

Answer 7

depression related to abnormality in three main NT:
serotonin, noradrenaline and dopamine

Question 8

What is the role of serotonin, noradrenaline and dopamine usually?

Answer 8

serotonin - calming and inhibiting action

noradrenaline - affects motivation, ability to focus, energy

dopamine - pleasure, satisfaction and reward

Question 9

How is serotonin implicated in depression?

Answer 9

decrease in serotonin is linked to depression

Imaging studies show abnormalities in serotonin receptor density and in transporters in people with depression

Question 10

What is evidence of serotonin involvement

Answer 10

Drugs which block serotonin re-uptake can ameliorate depression

Question 11

what is the limitations of serotonin involvement

Answer 11

recent review suggests no consistent evidence of association between serotonin and depression

no support for the hypothesis that depression is caused by lowered serotonin activity or concentrations

Question 12

How is noradrenaline implicated in depression?

Answer 12

regulating emotions
engaged in arousal
activities that reflect ability to concentrate

depressed mood is associated with a deficiency of noradrenaline in areas such as the brain stem and the locus coeruleus which projects to the limbic system, involved in regulating emotions

low levels of noradrenaline - emotional withdrawal, concentration and memory deficits

Question 13

what is evidence of noradrenaline involvement

Answer 13

Drugs which block noradrenaline re-uptake can ameliorate depression

Question 14

How is dopamine implicated in depression?

Answer 14

low dopamine levels may explain low sense of pleasure and reward in depression

inability to experience pleasure - one of the symptoms required for diagnosis

imaging studies show abnormalities in dopamine receptor density and in transporters in depressed patients

Question 15

What are the key findings in studies of NT

Answer 15

in depression NT are involved in:

-circuits that regulate emotional arousal

-regulate a reward network (ventral striatum with orbitofrontal and media prefrontal regions)

Question 16

what are limitations of findings

Answer 16

data makes it unclear whether NT abnormalities reflect a deficit, a consequence, a risk factor, or a compensatory mechanism in depression

the involvement of NT does not mean they cause depression

Question 17

what may cause these limitations

Answer 17

depression is a heterogeneous disorder

NT are part of a complex system that interacts with brain structure and function, genetics and the environment

Question 18

what brain regions are implicated in depression

Answer 18

hippocampus
anterior cingulate cortex
prefrontal cortex

Question 19

what is hippocampus like in depression

Answer 19

hippocapmmus is smaller in patients with depression than controls

smaller by 20%

chemical - cortisol which is released to alert the body to react to stimuli that are considered to be dangerous

when cortisol is chronically released, it would damage certain areas of the brain, one being hippocampus

that results in reduction in the ability to encode new information - hippocampus is key area for memory and encoding

Question 20

what happens to hippocampus if you leave depression untreated

Answer 20

leaving depression untreated for certain amount of time leads in consistent reduction in the volume of hippocampus

Question 21

what is the role of anterior cingulate cortex in depression

Answer 21

engaged in tasks that require resolving a conflict

engaged in memorising information

healthy controls were able to remember a short paragraph - activation in anterior cingulate and hippocampus

patients with depression were not performing well in memory task - lack of activation in these regions

Question 22

what is the role of prefrontal cortex in depression

Answer 22

patients and healthy controls viewed emotional and neutral film clips

patients with depression were less good at a task that required processing emotional stimuli

activated prefrontal cortex more than healthy controls

indicated dysfunctional use of these areas

Question 23

what are the problems with brain imaging in depression

Answer 23

despite the fact that this info is useful, it has little impact on clinical practice

because are findings contributing to the cause of depression or result of having depression

Question 24

how to address these issues

Answer 24

look at ppt longitudinally

try to test ppts before the onset of illness - recruit at risk ppts - those who might have a family history of depression and are more likely to develop depression

Question 25

what have brain images shown about studying people at risk of depression

Answer 25

3 groups:

-at risk ppts
-healthy controls
-patients with depression

Results:
1. at risk group had smaller right hippocampal and dorsolateral PFC volumes than controls

2. at risk groups had smaller right hippocampal than patients with depression - those ppts with depression were under treatment and the treatment helped to ameliorate the symptoms and some of the brain features

Question 26

what have family studies shown about genetic influence in depression

Answer 26

children of depressed parents have 50% chance of developing a disorder of some kind

20-40% chance of developing depression

Question 27

what have twin studies showed

Answer 27

higher concordance rates among monozygotic than dizygotic twins - supports genetic influence

heritability of depression is thought to be 31-42%

Question 28

how do we measure genetic effects through molecular genetics

Answer 28

study of chromosomes and gene expressions

Question 29

genetic and environmental effects

Answer 29

study of genes involved in regulating serotonin

1,037 children assessed at ages 3,5,7,9,11,13,15,18,21,26

looked at whether genes were predicting the possibility of developing depression when this was combined to being exposed to stressful events

whether ppts had 2 short alleles which are associated with decreased serotonergic function - and therefore highest risk of developing depression

1 short and 1 long allele - some risk

2 long allele - little risk

measure the number of stressful life events

RESULTS:
group that has 2 short allele + stressful life events = increased risk of self-report depression symptoms

when there is a genetic profile combined with stress this results in higher probability of developing depression

when there are no stressful life events, the 3 groups are equal in terms of self reported depression symptoms

so allele alone do not correspond to depression. only when they are combined with stressful situations

Question 30

What is depression like in late life

Answer 30

depression common in ageing

this is typically associated with health problems

less than 1/4 of older adults with depression receive treatment

low mood is common and often undiagnosed

in late life depression, treatment is not often successful

even if mood is stabilised there are still residual cognitive deficits

Question 31

what is vascular depression

Answer 31

vascular damage that accumulates with age

vascular damage reduces integrity of white matter - some parts of the brain are less effective at communicating with each other

it disrupts the circuits that underlie emotional regulation - likely to result in late life depression