Neurobiology of affective disorders

Question 1

What are the two types of classification of depression?

Answer 1

Unipolar and Bipolar

Question 2

Give examples of types of unipolar depression.

Answer 2

Mixed anxiety and depression,
Depressive episode,
Recurrent depressive,
Dysthymia persistent & mild( depressive personality)

Question 3

Give examples of types of bipolar depression.

Answer 3

Bipolar affective disorder with manic episodes &

Cyclothymia persistent instability of mood

Question 4

What are the brain areas involved in depression?

Answer 4

Prefrontal cortex, hippocampus, amygdala and nucleus accumbens

Question 5

A PET scan of a patient with unipolar depression may show what?

Answer 5

An increased metabolic activity in the amygdala

Question 6

What is the nucleus accumbens associated with?

Answer 6

Reward circuits. Whenever we do something that is rewarding, the DA neurons in the VTA are activated and these project to the nucleus accumbens resulting in an increase in DA levels.

Question 7

What happens to the volume of all the brain regions associated with depression, over time?

Answer 7

Decrease

Question 8

Seligman’s learned helplessness study (1975) found that…

Answer 8

Dogs that previously couldn’t escape the shock (learned helplessness condition), stayed on the side of the shock even when escape was possible.

Question 9

How does Seligman’s learned helplessness theory apply to depression?

Answer 9

When people believe they have no control over what happens to them, they begin to think, feel and act as if they are helpless. This helplessness can lead to depression.

Question 10

Seligman’s dogs in the learned helplessness condition recovered after 48 hours. What was Weiss’ explanation for this?

Answer 10

Brain noradrenaline levels decrease shortly after exposure but recover 48 hours after unavoidable stress session.

Question 11

The Monoamine hypothesis of depression states that depression is due to…

Answer 11

depletion of monoamines such as noradrenaline, serotonin and dopamine.

Question 12

What evidence supports the Monoamine hypothesis?

Answer 12

Drugs that deplete catecholamines are said to express depressive effects in humans and sedation in animals.

Drugs that are used as antidepressants ( Dopa, imipramine and MAO inhibitors) prevent reserpine in animals.

Question 13

What are 2 limitations of the theory?

Answer 13

1. Too simplistic

2. Delayed action of therapeutic effect

Question 14

Noradrenergic hypothesis of depression states that depression is due to…

Answer 14

reduced levels of NA, supported by the effects of antidepressants increasing NA anabolism.

Question 15

What is serotonin involved in?

Answer 15

Pain sensitivity, emotionality and response to negative consequences.

Question 16

Serotonin hypothesis of depression states that genetic variation in the gene for serotonin transporter causes which biological and behavioural phenotype?

Answer 16

Biological phenotype- altered response to stress

Behavioural phenotype- increased depression after stressful life events.

Question 17

List as many drugs as you can that are used to treat depression.

Answer 17

1. Monoamine oxidase inhibitors- e.g iproniazid
2. Tricyclics- inhibit reuptake of noradrenaline and serotonin
3. SSRI’s-inhibit reuptake of serotonin by blocking the transporters-e.g prozac

Question 18

What enzyme breaks down serotonin?

Answer 18

Monoamine oxidase

Question 19

What do monoamine transporters, DAT, SERT and NET do?

Answer 19

They remove neurotransmitters from outside cells and recycle back into the releasing terminals.

Question 20

What other type of drugs used to treat depression is similar to tricyclics?

Answer 20

SNRI’s- selective serotonin/noradrenaline reuptake inhibitors
e.g venlafaxine

Question 21

Cipriani et al (2018) did a meta- analysis which showed that…

Answer 21

Antidepressant drugs work better than placebo overall.

Question 22

Harmer et al, 2009 suggested that antidepressants may work behaviourally by..?

Answer 22

influencing affective bias. Depressed people are slower to rate faces as happy and more sensitive to negative bias.

Question 23

What is Cortico-trophin-releasing factor (CRF)?

Answer 23

It is a neuropeptide mediator of stress responses in the CNS.

Question 24

Where is CRF expressed?

Answer 24

It is expressed in the paraventricular nucleus of the hypothalamus

Question 25

CRF coordinates the release of which hormone?

Answer 25

adrenocorticotrophic hormone (ACTH) from the pituitary gland.

Question 26

What does the HPA axis stands for?

Answer 26

Hypothalamic Pituitary Adrenocortical system

Question 27

Once CRF is released in response to an environmental stressor, what sequence of events occur next?

Answer 27

ACTH is then released from the pituitary.

This in turn releases cortico-steroids from adrenal glands.

When the stressor is terminated, negative feedback shuts down the HPA axis.

Question 28

Depression is associated with increased activity of the HPA axis, elevated cortisol levels and enlarged adrenal glands. This suggests a link between depression and…

Answer 28

stress

Question 29

Which disease involves excessive secretion of corticosteroids?

Answer 29

Cushing’s disease

Question 30

What is the relationship between neurogenesis and depression?

Answer 30

A protein that regulates neurogenesis, brain derived neurotrophic factor (BDNF) is reduced in depression.

Question 31

Where does neurogenesis occur in the brain?

Answer 31

Hippocampus and olfactory bulb

Question 32

What 3 things increase neurogenesis?

Answer 32

1. Exercise
2. Environmental enrichment
3. Antidepressants

Question 33

What 3 things decrease neurogenesis?

Answer 33

1. Stress
2. Sleep deprivation
3. Age