Heston (1966) - Example adoption study

Question 1

What is the aim of this study?

Answer 1

To see how many adopted kids of biological mothers with schizophrenia would develop schizophrenia themselves

Would provide evidence for genes in schizophrenia

Question 2

What is the sample of the experimental group?

Answer 2

47 subjects, all born between 1915-1945 to schizophrenic mothers confined to Oregon State psych hospital

Kids adopted at birth due to mother’s schizophrenia

Question 3

What is the control group sample?

Answer 3

50 control subjects, mothers mentally healthy

Question 4

What was the method?

Answer 4

1. Ppts asked to personal interview - interview standardised, structured, general medical + environmental questionnaire
2. Adults interviewed to see whether any of them went on to develop schizophrenia themselves
3. Info gathered + evaluated blindly by 2 independent psychiatrists + a final evaluation by a 3rd psychiatrist

Question 5

What was the risk of developing schizophrenia if 1 parent had it?

Answer 5

10%

Question 6

What were the results of the study?

Answer 6

• 5/47 adults interviewed whos moms had schizophrenia were hospitalised with schizophrenia
• 10% of adopted kids of schizophrenic moms developed schizophrenia
• Non of control group developed schizophrenia, showing experience of adoption wasnt a factor

Question 7

What is the conclusion?

Answer 7

Results provided powerful evidence for role of genes in schizophrenia

No evidence for environmental factors for schizophrenia