ABSTRACT
In order to study the possible vulnerability in the markers of schizophrenia, offsprings of the schizophrenic parents(n=28), offsprings of the alcohol dependent parents(n=18), and offsprings of the psychiatrically normal persons(n=41) were examined for their sustained attention and sensory register by means of Continuous performance test(CPT) and Span apprehension task(SPAN) respectively. The results were as follows: 1) The offsprings of the schizophrenic parents showed a significant deficit in the sustained attention as manifested in the data of CPT by significantly lower hit rate and sensitivity, compared with the offspring of the alcohol dependent parents and those of the psychiatrically normal persons. No difference was evident in the false alarm rate and response bias among three groups. There was no difference in all variables of the CPT between the offsprings of the alcohol dependent parents and those of the psychiatrically normal persons. 2) The deficit in the sustained attention as revealed by lower hit rate and sensitivity was not apparent in the first part of the CPT. However it emerged and aggravated itself as the test continued in the offsprings of the schizophrenic parents only. 3) Proportion of subjects falling in the extreme low sensitivity of lower 10% of the normal controls was significantly higher in the offsprings of the schizophrenic parent group as compared with the offsprings of the alcohol dependent parents and those of the psychiatrically normal persons with a rate of 29%, 17%, and 10% respectively. 4) No significant difference was noted in all variables of MMPI among normal controls, index group, and the extreme low CPT sensitivity subgroup of index group. 5) The offsprings of the schizophrenic parents showed a significantly delayed response in the time to correct and incorrect response in SPAN compared to offsprings of the alcohol dependent parents and those of the psychiatrically normal persons. No difference was evident in the number of correct response, number of incorrect response, and number of no response among three groups. There was no difference in all variables of the SPAN between the offsprings of the alcohol dependent parents and those of the psychiatrically normal persons. These results suggest that a subgroup of the offsprings of schizophrenic parents may suffer from the deficit in the sustained attention which may be a vulnerability marker of schizophrenia.