Heston 1966

• Aim

  To see if schizophrenia is inherited from mother

  The term 'schizophrenogenic mother' was in use at time which suggested a parent can cause it by creating a 'distorted family environment'
• Procedure 1

  adoption study which separated nature from nurture

  P's were born between 1915-1945 to schizophrenic mothers in an American psychiatric hospital who had been put up for adoption

  Researchers ensured mothers had diagnosis of schizophrenia, evidence of behaviour consistent with this, no other diseases, and baby and mum separated from birth
• Procedure 2

  74 children satisfies conditions but some dropped due to death, contact w mum etc and so 58 remained - matched for controls.

  More deaths or no follow ups meant final sample was 47 experimental Ps (30 male and 17 female) and 50 controls (matched w sex, time in childcare etc)

  Fathers psychiatric state not checked but none known to be hospital patients
• Checked for

  Police records, school records, any psychiatric hospital records

  IQ score, family & friends & employers contacted

  Personal interviews (25/97 refused or unavailable)

  Newspaper files reviewed

  Social class of first home and current social class
• How scores made

  2 psychiatrists evaluated dossier complied on each P blindly and independently. Heston made 3rd evaluation.

  Diagnosis of schizophrenia given only when all 3 raters agreed + also diagnosed by psychiatric hospital

  Score pf 1-100 assigned to each P regarding this as psycho-social disability (100 highest) and scored below 75 indicate psychiatric symptoms become troublesome
• Findings

  No differences in children, divorces, marriage rates, social groups, years serving armed forces or school years

  Differences in psycho-social disability (65.2 v 80.1), schizophrenia (5 v 0), time spent in psychiatric institutions (11 v 2 w over a year), IQ defiency (4 v 0), crimes

  Rate of schizophrenia in experimental Ps was 10.6%
• Conclusions

  Findings support influence of genes in schizophrenia and that inheritance also contributes to psycho-social disability

  Must be other possible factors influencing development of schizophrenia because half of experimental Ps were successful adults w artistic talents not found in control group
• Weakness 1

  Secondary data such as hospital records were collected w could be more subjective than primary data - open to interpretation
• Weakness 2

  Psychiatric status of father not checked which may have been a contributing factor to schizophrenia
• Strength 1

  Heston established inter-rater reliability when analysing patients records as he used multiple data sources in his study + 3 psychiatrists (raters) who agree
• Strength 2

  Thorough - gathered lots of info on 47 Ps and 50 control adoptees