Adoption Study: Kety et al (1968): Flashcards
What was the Aim?
To establish if there is a genetic basis for SZ by comparing the adoptive family and the biological family of SZ patients.
Who were the ppts?
34 SZ patients, Danish Adoption Register. Aged 20-43. Split into 3 groups, chronic sufferer, ST sufferer, borderline diagnosis. 33 healthy controls matched, based on gender, age, social class.
How did they track down relatives?
Using records, they tracked down 463 relatives and assessed their mental health. The relatives were diagnosed by 4 psychiatrists who did noy know their relationship to the patients and diagnosed into 3 categories, B= Just like the SZ ppt, D= Uncertain level of SZ, C= Inadequate personality.
What were the results?
Found more signs of SZ in both adoptive child and their bio family rather than their adoptive family. More SZ were found in the adoptive child biological family than in the control biological families.
What was the conclusion?
SZ seems to have a genetic component as adoptees were more likely to have SZ in their bio family than adoptive. Adoptive sample was also more likely to have SZ in their bio than the control sample.
One Strength: Matched Pairs:
One strength of the study is that they used a matched pairs design as 33 healthy controls were matched to the SZ ppts on gender, age and social class of adoptive family. This allowed Kety et al to make comparisons to the control group whilst controlling for individual differences.
One Weakness: Population Validity:
One weakness of the sample is that it is not generalisable to the wider population as they were taken from the Danish Adoption Records. This is a weakness because the study lacks population validity as it can’t be generalised to the non-Danish population.
