Unipolar Depression: One Biological explanation (Neurochemical explantion)

Question 1

What was the first hypothesis developed to explain the role of nuerotransmitters in depression

Answer 1

monoamine depletion hypothesis

Question 2

Monoamine depletion hypothesis: What did the monoamine depletion hypothesis state

Answer 2

Stated that depression was caused by low levels of monoamine nuerotransmitters.

Question 3

Monoamine depletion hypothesis: What are the monoamine nuerotransmitters

Answer 3

serotonin, noradrenaline and dopamine

Question 4

Monoamine depletion hypothesis: why were the monoamine nuerotransmitters were the suggested cause

Answer 4

because of their role in regulating the brains function in the limbic system

Question 5

Monoamine depletion hypothesis: what is a problem of this hypothesis

Answer 5

it didn’t consider the interaction between these nuerotransmitters

Question 6

Monoamine depletion hypothesis: how do the monoamine nuerotransmitters interact?

Answer 6

Its a balance of the nuerotransmitters that cause depression, serotonin levels control levels of noradrenaline, if serotonin drops so does noradrenaline

Question 7

Why did researchers start looking at nuerotransmitter receptors as well

Answer 7

because antidepressent drugs didn’t increase availability of nuerotransmitters, suggesting theres more to depression than monoamine depletion

Question 8

What hypothesis was developed as a result of the research on antidepressant drugs?

Answer 8

receptor sensitivity hypothesis

Question 9

Receptor sensitivity hypothesis: what is it

Answer 9

states that depression is caused due to changes in sensitivity of the postsynaptic receptors

Question 10

Receptor sensitivity hypothesis: what happens to serotonin receptors in depression

Answer 10

they become super sensitive

Question 11

Receptor sensitivity hypothesis: what happens as a result to the seretonin receptors becoming sensitive

Answer 11

nuerons respond as if they’re overstimulated, producing less serotonin causing a negative feedback loop

Question 12

BDNF hypothesis: what is BDNF

Answer 12

BDNF is a protein that feeds nuerons with nutrients they need to function. Plays a big role in nueral plasticity

Question 13

BDNF hypothesis: how does BDNF link with depression

Answer 13

People with depression have been shown to have low levels of BDNF

People with depression have stress, high levels of stress turn of BDNF, leading them vulnerable to death or shrinkage

Question 14

What is a weakness of the monoamine hypothesis

Answer 14

Cannot explain theraputic delay commonly experienced.

Question 15

Weakness of monoamine hypothesis: how long does it take for people with depression who take antidepressants to see improvements

Answer 15

4-6 weeks.

Question 16

BDNF hypothesis: why is the 4-6 week delay hard to explain

Answer 16

because serotonin levels increase and become normal after about 1 week.

Question 17

What is a strength of the BDNF hypothesis

Answer 17

there are 2 main sources of evidence for BDNF in depression

Question 18

strength of BDNF: what are the 2 main sources

Answer 18

• studies show, using blood samples, theres a negative correlation of BDNF levels in the blood and severity of depression symptoms
• study of BDNF levels in post mortem brains of people who suffered depression show low levels of BDNF in hippocampus and prefrontal cortex

Question 19

strength of BDNF: what does the evidence show

Answer 19

theres a clrea link between BDNF levels and depression

Question 20

what is a weakness of the biological explanation for depression

Answer 20

most of the evidence is observed correlation, correlation does not equals causation.

Question 21

Weakness for biological explanation: what does this mean as a result of the evidence being mostly observed correlations

Answer 21

It only shows a connection. Means we do not know if unusual brain activity causes depression, or if depression causes unusual brain acitivity.

Question 22

What is a strenght of the application of the explanation

Answer 22

led to the development of antidepressant drugs

Question 23

Strength of application of biological explanation: what do these new developments of antidepressants mean

Answer 23

both serotonin and noradrenaline levels can now be targeted where as other drugs only target 1 nuerotransmitter

Question 24

Strength of application of biological explanation: why is this a strength

Answer 24

it may improve quality of life and is a good alternative to treatment resistant patients