High Risk Studies

Twin studies: how large is the genetic component of risk
1. Schizophrenia Riley & Kendler 2006
  1. 50% Monozygotic twins 17% Dizygotic
2. Unipolar depression Kamali & McInnis 2011
  1. 46% Monozygotic 20% dizygotic
3. Eating Disorder Thornton et al 2011
  1. Anorexia 70% monozygotic 20% dizygotic
  2. Bulimia 23% monozygotic 9% dizygotic
4. Substance abuse Kaiji 1960
  1. Alcoholics 54% monozygotic 28% dizygotic
Adoption studies: are genetic factors evident when shared familial environment is controlled? Nature/nurture debate
1. Substance abuse Cadoret et al 1995
  1. Adopted individuals with alcoholic biological parents show higher rates of alcohoholism than those with non alcoholic biological parents
2. Schizophrenia Riley & Kendler 2006
  1. 4.9% adopted individuals with schizophrenic biological mothers have schizophrenia
  2. 9.1% of adopted individuals with schizophrenic biological mother developed a schizophrenia spectrum disorder eg: schizoid
  3. 1.1% of adopted individuals with control mothers developed schizophrenia
Criticism
1. Lack external validity
  1. Twins have different life experience
  2. Very small sample size
2. Selective placement: children matched to adopted family/environment that resembles biological
3. Diagnosticians vary
  1. A lot of disorders share similar symptoms eg; schizophrenia & bipolar
4. Self fulfilling prophecy
Family studies: does risk accumulate in relatives
1. Schizophrenia Riley & Kendler 2006
  1. 4.8%, lifetime morbid risk of developing schizophrenia 10 times higher than morbid risk of control group relatives 0.5%
2. Unipolar depression Kamali & McInnis 2011
  1. 20% of relatives were also depressed compared to 10% of the general population
3. Eating disorder Thornton et al 2011
  1. Relatives are 6 times more likely to have/develop an eating disorder

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High Risk Studies

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	Created by sterling-l over 9 years ago