Heston 1966 (adoption study)

• What is an adoption study?

  > Environment of adoptive children is not the same as that of their biological families

  > Assess nature (genes) vs nurture (environment)

  > Uses a concordance rate to compare children to biological parent and their adoptive parent
• What is a concordance rate?

  The probability that a pair of individuals will both have a certain characteristic
• What was Hestons study regarding?

  Psychiatric disorders in foster home reared children of schizophrenia mothers
• What was Heston's aim?

  To investigate whether nature or nurture was responsible for the development of schizophrenia by using an adoption study to separate at these factors
• What was the sample of this study?

  > Participants were born between 1915-1945 to schizophrenia mothers in an American psychiatric hospital

  > Selected if the mother put them up for adoption and had schizophrenia, initially 74 kids met the criteria

  > 16 were dropped due to the death or having contact with their mother

  > 58 participants were matched with controls on sex, type of eventual placement and length of time in childcare

  > 47 participants (30 male + 17 female) and 50 controls who were up for adoption (33 male + 17 female)
• What was the procedure of this study?

  > To assess psychiatric status, different sources of data like school records, psychiatric hospital records and interviews

  > Two psychiatrists blindly and independently evaluated the information whilst Heston did a third evaluation

  >Only diagnosed with schizophrenia if all three raters agreed

  > A score of 1-100 was assigned to each participant regarding psycho-social disability where scores below 75 indicates psychiatric symptoms becoming troublesome
• What were the results of this study?

  > Average scores of psych-social disability of children born to schizophrenic mothers was 65.2 compared to controls who scored 80.1 - A score of 75 or less is related to schizophrenia

  > Rate of schizophrenia in children with schizophrenic mothers was 10.65 compared to controls who had 0%

  > Concordance rate of 10% if one parent has schizophrenia