Flashcards in Biological explanations of depression Deck (13):
Genetic factors: family study
Harrington et al (1993) studied probands first degree relatives and found 20% have depression compared to 10% of the population at large
Genetic factors: twin study
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
Genetic factors: adoption study
Wender et al (1986) studied biological relatives of adopted individuals who had depression. their biological parents were also likely to have depression
Genetic factors: genes study
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).
Neurotransmitter dysfunction: how was noradrenaline linked to depression in the 60s?
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)
Neurotransmitter dysfunction: noradrenaline correlation evaluation?
Leonard (2000) found drugs which increase noradrenaline levels decrease depressive symptoms. however this is correlational.
Neurotransmitter dysfunction: how has serotonin linked to depression?
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
Neurotransmitter dysfunction: support for serotonin and depression
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.
Neurotransmitter dysfunction: real life application for neurotransmitters?
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.
Cortisol hypersecretion: how is cortisol linked to depression?
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
Cortisol hypersecretion: unsupportive research
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.
Cortisol hypersecretion: real world application
O'Keane and Marsh (2007) claimed that during pregnancy high cortisol levels are needed, however if their too high it can cause infant death.