The hormonal environment in utero as a potential aetiological agent for schizophrenia

There is consistent evidence in the literature that the foetal neurodevelopmental period is crucial for the genesis of schizophrenia later in adult life. There are also strong indications that the schizophrenic illness has sexually dimorphic features. A hypothesis consistent with both findings is that sexual hormones may act as aetiological agents for schizophrenia during the foetal period influencing the neurodevelopment in a differential way in males and females. The aim of this study is to verify this hypothesis exploiting the correlation between fingers' length in adults and hormonal concentrations in utero, which has been demonstrated in previous studies. More specifically, the literature shows that the lengths of the second and fourth finger in adults are proportional to the foetal concentrations of respectively oestrogens and androgens. When the sample of patients suffering from schizophrenia analysed in this study was compared with healthy subjects, it was observed that the average length of the second digit in the female schizophrenic sample resulted significantly shorter than in the female controls. There was no significant difference when the male schizophrenic sample was compared with male controls. The result of the study is, therefore, compatible with the hypothesis that oestrogenic hormones protect female foetuses from damage during the neurodevelopment in utero and ultimately give more benign characteristics to the schizophrenic illness in women.