Biological Causes of Depression

Question 1

What are 4 possible biological causes of depression?

Answer 1

1. Genes
2. Cortisol hypersecretion
3. Monamine hypothesis
4. Noradrenaline

Question 2

How are genes a possible biological cause of depression?

Answer 2

It’s possible that a predisposition for depression may be inherited - relatives of those with depression have a 20% risk of developing the disorder, compared to 10% in the general population.

Question 3

What are the 2 different types of twins?

Answer 3

Monozygotic and dizygotic.

Question 4

What did Allen find, relating to concordance rates of depression in twins?

Answer 4

CR of 40% in MZ twins and 11% in DZ twins.

Question 5

What did McGuffin find, relating to concordance rates of depression in twins?

Answer 5

109 pairs of twins - mixed MZ and DZ.

CR of 46% in MZ twins and 20% in DZ twins.

Question 6

What adoption study did Wedner et al carry out, relating to the genetic explanation of depression? (Method, findings, what does this suggest?).

Answer 6

Studied biological relatives of adopted people who had been hospitalised for severe depression.
Found - much higher incidence of severe depression in these relatives, than in those of a non-depressed control group.

Question 7

What is one argument of the genetic explanation?

Answer 7

Nature vs nurture argument - difficult to separate and isolate the influences of nature and nurture as twins usually share the same environment.

Question 8

What are 4 other issues of the genetic explanation of depression?

Answer 8

1. Population validity - samples used in most studies are very small - can’t generalise to rest of the population.
2. Reductionist - ignores other social and psychological factors that also have supporting research.
3. Deterministic - ignores the fact that not everyone who has relatives with depression also suffers with it.
4. CR are not 100% - suggests that it is only a partial explanation and that there are other factors involved.

Question 9

What is cortisol?

Answer 9

Cortisol is a stress hormone that is released by the adrenal gland.

Question 10

How is cortisol hypersecretion a possible explanation of depression?

Answer 10

Depressed patients often have high levels of cortisol, which can lead to depressive symptoms.
When cortisol are levels are lowered by using drug treatments, patients depression is often lifted.

Question 11

What did Memeroff find, relating to cortisol hypersecretion?

Answer 11

There is an increase in activity in the adrenal gland in depressed patients compared to a control group.
Over activity in the adrenal glans = high levels of cortisol.

Question 12

What contradictory evidence did Strickland find, relating to cortisol hypersecretion being an explanation of depression? (Findings, suggest, 1 criticism).

Answer 12

Found no evidence of increased levels of cortisol in a large group of women. But there were elevated cortisol levels in p’s who had recently experienced stress, but weren’t depressed.
Suggests - not everyone w/ high cortisol levels becomes depressed.
1. Females - can’t gen to males - low ext and pop val.

Question 13

How does the monoamine hypothesis attempt to explain depression?

Answer 13

A neurotransmitter involved in depression is serotonin. This hypothesis suggests that low levels of serotonin = depression.

Question 14

What study did Rosen et al carry out into the monoamine hypothesis explanation of depression?

Answer 14

Compared substances found in urine of depressed p’s and control group.
Found - compounds produced as a byproduct of the action of serotonin were present in larger amounts in the depressed p’s urine - more enzymes = altered levels of serotonin.
After introducing drugs that block serotonin uptake (balance the levels of serotonin) e.g. prozac, p’s depressive symptoms often improved.

Question 15

What study did Delgado carry out into the monoamine hypothesis explanation of depression?

Answer 15

Placed p’s on a diet that lowered their levels of tryptophan (a precursor of serotonin).
Found - depressive symptoms returned. BUT those who had never been depressed didn’t experience a low mood when their diet was changed.

Question 16

What do Delgado’s findings suggest?

Answer 16

Low levels of serotonin can’t be the only cause of depression as a diet low in tryptophan was only effective on previously depressed people - questions validity of research and only offers a partial explanation.

Question 17

How does noradrenaline attempt to explain depression?

Answer 17

Low levels of noradrenaline have been found in depressed patients.
Postmortem examination also revealed increased densities of noradrenaline receptors - suggesting physical changes in the body to cope with low levels of it.

Question 18

What are 5 criticisms of biological explanations of depression?

Answer 18

1. All results are correlational - cause and effect cannot be established - only proves a link, doesn’t prove that it is the definitive reason.
2. Individual differences - e.g. not everyone who has depression is helped by serotonin based drugs and not everyone w/ low serotonin levels becomes depressed - - suggests other causes of the disorder.
3. Deterministic - states that depression is determined by biological factors and doesn’t consider free will or individual differences, e.g. not everyone who has low serotonin levels becomes depressed.
4. Reductionist - ignores other important factors e.g. social and psychological factors that also have supportive research.

Question 19

What is 1 criticism of biological treatments of depression?

Answer 19

1. Biological treatments only treat symptoms of the disorder, whereas CBT is better at treating cause and ha slower relapse rates.