Biological explanations of depression

Question 1

Genetic factors: family study

Answer 1

Harrington et al (1993) studied probands first degree relatives and found 20% have depression compared to 10% of the population at large

Question 2

Genetic factors: twin study

Answer 2

McGuffin et al (1996) studied 177 probands and their same sex co-twins. concordance rates were 46% for MZ twins and 20% for DZ twins

Question 3

Genetic factors: adoption study

Answer 3

Wender et al (1986) studied biological relatives of adopted individuals who had depression. their biological parents were also likely to have depression

Question 4

Genetic factors: genes study

Answer 4

Kendler et al (1995) studied female co-twins and found both were likely to be depressed. however, negative life events also had an impact (diathesis stress model).

Question 5

Neurotransmitter dysfunction: how was noradrenaline linked to depression in the 60s?

Answer 5

Bunney et al (1965) found indirect markers of noradrenaline in the brain was often low.
post-mortems also showed increased lumbers of noradrenaline receptors in suicide victims (up-regulation)

Question 6

Neurotransmitter dysfunction: noradrenaline correlation evaluation?

Answer 6

Leonard (2000) found drugs which increase noradrenaline levels decrease depressive symptoms. however this is correlational.

Question 7

Neurotransmitter dysfunction: how has serotonin linked to depression?

Answer 7

there was originally a link as there was a low amount of serotonin bi-product in patients cerebrospinal fluids.
this was confirmed by the introduction of prozac which stops re-uptake of serotonin and therefore decreased syptoms

Question 8

Neurotransmitter dysfunction: support for serotonin and depression

Answer 8

Ruhe et al (2007) gave patients an amino acid mixture which decreased serotonin levels, patients experienced a relapse of symptoms. however non-depressed ps have no effects. ethics.

Question 9

Neurotransmitter dysfunction: real life application for neurotransmitters?

Answer 9

Kraft et al (2005) studied 96 patients with major depression who were treated for 6 weeks with a dual serotonin-noradrenaline SNRI. they showed a positive response compared to placebo group.

Question 10

Cortisol hypersecretion: how is cortisol linked to depression?

Answer 10

stress = pineal glands to release cortisol = reduction in serotonin = depressive symptoms
Dexamethasone usually suppresses cortisol, however doesn’t work in depressed patients; suggesting over activity of the HPA is a characteristic of depression

Question 11

Cortisol hypersecretion: unsupportive research

Answer 11

Strickland et al (2002) found no evidence of increased cortisol in a large group of depressed women. however, elevated cortisol were found in those who had experiences severe life events but were not depressed.

Question 12

Cortisol hypersecretion: real world application

Answer 12

O’Keane and Marsh (2007) claimed that during pregnancy high cortisol levels are needed, however if their too high it can cause infant death.

Question 13

Serotonin: pestiside users

Answer 13

Amr found depression was sig higher in pestiside users with at least 15 years exposure