Adoption Study: Kety Et Al (1968)

Adoption Study: Kety Et Al (1968)

1. ABOUT

   • AIM
     • To find out if there is a genetic basis for schizophrenia
   • DESIGN
     • independent groups design because it looks at the difference between biological drelatives and adoptive relatives of schizophrenia-sufferers
     • As adoption and schizophrenia are naturally-occurring variables, this is a natural experiment.
   • DV
     • The researcher's measured the prevalence of schizophrenia-related mental illness among family members.
   • SAMPLE
     • 34 schizophrenic patients taken from the Danish Adoption Register for Copenhagen
     • 33 mentally-healthy Controls were selected from the Danish Adoption Registry.

2. PROCEDURE

   • Kety used the Danish family records to locate adoptive and biological relatives of all the participants.
     • e tracked down 463 relatives and used the mental health register to assess their mental status.
   • A panel of 4 Danish psychiatrists used the medical records to diagnose the family members.
   • Once the diagnoses had been made, the identities were revealed and they were assigned to adoptive family groups (IA and CA) or to the biological family groups (IB or CB).

3. RESULTS

   • The research found more signs of schizophrenic spectrum disorders in the index participants' biological family than their adoptive family
   • They found more spectrum disorders in the index participants' biological families than in the Controls' biological families.

4. CONCLUSION

   • There seems to be a genetic component to schizophrenia because schizophrenic adoptees were more likely to have schizophrenia in their biological family than their adoptive family

5. EVALUATION

   • GENERALISABILITY
     • This study has a fairly large sample and covers a range of ages
   • RELIABILITY
     • Very reliable procedure and they replicated it in 1975, 1978 and 1994
   • APPLICATION
     • For families with a history of schizophrenia and people looking to adopt a child.
   • VALIDITY
     • Kety's American-Danish Adoption Studies tie in with earlier research like Gottesman & Shields (1966)
   • ETHICS
     • The participants in this study were not directly approached: only their data was analysed by the researchers
       • This could be done under Danish laws without needing consent from the participants.