Mood Disorders

1
Mood Disorders

• Biological explanations
• Genetics
• Neurochemical abnormalities

www.psychlotron.org.uk
2
Mood Disorders Genetic

• Zubenko et al (2001)
• Family history 50 of FD relatives, 25 of SD
  relatives also had mood disorder
• Relatives had increased risk of suicide liver
  disease
• McGuffin et al (1996)
• MZ 46, DZ 20
• MZ concordances substantially inflated in more
  serious cases

www.psychlotron.org.uk
3
Mood Disorders Genetic

• Depression tends to run in families
• The closer the relationship with a sufferer, the
  more likely a person will have a mood disorder
• Genetic evidence is strongest for most severe
  forms of the disorder
• Concordance rates also indicate a substantial
  environmental contribution

www.psychlotron.org.uk
4
Mood Disorders - Neurochemical

• Abnormality in neurochemicals
• Too much or too little of some chemicals e.g.
  serotonin affects the functioning of the brain
  this might have an effect on emotion regulation

www.psychlotron.org.uk
5
Mood Disorders - Neurochemical
www.psychlotron.org.uk
6
Mood Disorders - Neurochemical

• Noradrenanaline (NA)
• Too little leads to depression, too much to mania
  (catecholamine hypothesis)
• Serotonin (5-HT)
• Regulates NA activity, so too little allows
  abnormal fluctuations in NA (permissive amine
  hypothesis)
• Dopamine (DA)
• Involved in reinforcement, so too little results
  in anhedonia (dopamine hypothesis)

www.psychlotron.org.uk
7
Mood Disorders - Neurochemical

• Some evidence (but not all) suggests that mood
  disorder patients have abnormal levels of NA
  5-HT
• Might be sensitivity to neurotransmitters that
  matters, not raw levels in brain
• Interactions between neurotransmitters are poorly
  understood likely to be complex
• Problems with direction of causality

www.psychlotron.org.uk
8
Mood Disorders - Neurochemical

• Drugs that alter brain levels of NA 5-HT are
  effective in treating depression in about 60 of
  cases
• So what about the non-responsive patients?
• Relapse when drugs are discontinued?
• Treatment-aetiology fallacy?

www.psychlotron.org.uk