From a theory that stress accounts for the high proportion of daughters born to schizophrenic women, the relation of maternal stress to fertility and sex ratio was examined. Twelve female rats were stressed in wire-screen cocoons for four hours a day for one week before conception. The influence of the father on sex ratio and fertility was controlled by mating the same males with stressed and with unstressed females. Stressed females gave birth to significantly fewer males and significantly smaller litters than unstressed controls. The male zygote and fetus are evidently more vulnerable to stress than their female counterparts.
An earlier study by the authors reported that children who become schizophrenic adults show a significant decline in intelligence-test performance between early and late childhood. The present study compares the earlier results with new control and standardization groups and determines that the previous conclusions were not justified. An earlier study (Lane & Albee, 1963) reported that school-age children who later become schizophrenic adults show a significant decline in intelligence-test performance between early and late childhood. Because a control group of 872 children from the same school system showed a slight gain in IQ score on the same two tests taken at the same ages, it was concluded that the decline in IQ represents a genuine decrease in intellectual function which distinguishes preschizophrenics from other children. The conclusions of this study have been cited by others (Mednick, 1965; Segal, 1966; Yates, 1966). Recently, however, in a reexamination of the composition of the control group and of the problems involved in comparing results from two different intelligence tests, the authors became dissatisfied with these conclusions. Is the reported decline in intelligence during childhood related to socioeconomic factors that were not controlled or is it characteristic of schizophrenia? Does this loss in IQ points represent differences between two tests or a genuine decline in intellectual level? The majority of the future schizophrenics came from the lowest socioeconomic levels and generally scored below average even on the first test, while the children in the con
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