Gottesman and Shields (1966): Flashcards
What is the Aim?
To investigate if schizophrenia had a genetic basis.
Who were the ppts? And the Procedure.
62 schizophrenic patients, half male and half female. Ppts aged 19-64. Had all been patients in a large London Hospital. All had a twin. 24 MZ and 33 DZ identified using blood grouping, fingerprints and physical resemblance. Mental health measured by hospital notes.
What were the results?
42% MZ with SZ had a twin with a diagnosis of SZ and only 9% of DZ with SZ had a diagnosis of SZ. Average rate of general population is 1%. Identical twins are more likely to have SZ.
What was the conclusion?
The closer the genetic link the more likely both twins are to show SZ symptoms. MZ significantly lower than 100% so needs an environmental trigger.
One Strength: Quantitative Data:
One strength is that its quantitative data, so it allows comparisons to easily be made between MZ and DZ. This means that useful valid findings can be drawn about the basis of SZ.
One Weakness: Ecological Validity:
One weakness is that its not generalisable to the whole population since not everyone has a twin. Therefore, making the results less useful and lacking in ecological validity.
