• Created by: Lauren
  • Created on: 29-04-15 15:32


At least one symptom in category 1 = persistent depressed mood and/or pervasive anhedonia

and four+ of category 2 = e.g. difficulty concentrating

Types-> unipolar, bipolar, post-partum, dysthymia + SAD

Mz Twins 69% cc & Dz Twins 13% cc

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  • MAOIs inbihit MAO, an enzyme that breaks down excess monoamines in terminal buttons. However can lead to excess monoamines
  • Tricyclic antidepressants (antihistamines) show improvements in endogenous depression and encourages reuptake of 5-HT and NE to make the neurotransmitters active longer
  • SSRIs inhibit serotonin reuptake
  • ECT used as a treatment when epilepsy patients found reduced depression symptoms after a seizure
  • Sleep deprivation sometimes effective
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Further Theories into Causes

  • Monoamine hypothesis = insufficient activity of monoaminergic neurones - depression caused by monoamines antagonist
  • 5-hydroxyindoleactic acid = metabolite of 5-HT and suicidal depression is linked to low levels of this
  • Tryptophan depletion = used to make 5-HT and low tryptophan diets caused relapse even when participants were medicated. PET imaging show reduced activity due to tryptophan depletion especially in pf cortex
  • Drugs that increase release of 5-HT can temporarily inhibit activity of 5-HT neurones in brain but gradually become less sensitive (explanation for delay in drugs)
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