Heston (1966) Flashcards
aim
to see how many adopted children of biological mothers with schizophrenia went on to develop schizophrenia themselves
sample - experimental subjects
born between 1915 and 1945 to schizophrenic mothers confined to an oregon state psychiatric hospital
children had been adopted at birth because their mothers suffered from schizophrenia
sample - control group
matched group of 50 adoptees whose mothers were believed to be naturally healthy
controls - sex, type of eventual placement & length of time in childcare
why was a control group essential in this study
to eliminate the possibility that adoption itself might be responsible for schizophrenia
how was a numerical score used
numerical score moving from 100 to 0 with increasing psycho-social disability was assigned for each subject
scoring based on the landmarks of the Menninger Mental Health - Sickness Rating Scale (MHSRS)
procedure
subjects contacted by letter & asked to participate in a personal interview
interviews conducted in the homes of subjects
adults interviewed in order to see whether any had developed schizophrenia themselves
information evaluated
numerical scoring (MHSRS)
why were adults interviewed in this study
to see if any had developed schizophrenia themselves
how was the information evaluated
blindly and independently by two psychiatrists
final evaluation by third researcher
fourth researcher used if any disagreements arose in the results
high inter rater relaibility
results
5/47 adults interviewed whose mother suffered from schizophrenia had been hospitalised with it, 3 were chronically ill (10%)
none of the control group developed schizophrenia - suggests adoption is not a factor
significant excess of psycho-social disability in 1/2 born to schizophrenic mothers
what does none of the control group developing schizophrenia suggest
adoption isn’t a factor in developing schizophrenia
conclusion
provides evidence for the role of genetics in schizophrenia
no evidence for the role of environmental factors in schizophrenia
low generalisability
volunteer sample - may have shared characteristics so doesn’t represent target population
why did the MHSRS scale mean the study had higher reliability
reliable as a measure of incapacity as there was good agreement between the raters - fourth psychiatrist used when differences arose
researchers blind to hypothesis - bias eliminated and subjectivity reduced
what was the result of the researchers being blind to the hypothesis
bias eliminated and subjectivity reduced
why did standardised questions being used in the interviews increase reliability and what where they used for
used to ascertain mental health of the adopted individuals
the consistent questioning of the individuals made the study replicable
