Obstetrical complications and subsequent schizophrenia in adolescent and young adult offsprings: is there a relationship?, 2004
Schizophrenia is a psychiatric disease affecting around 1% of the population, the negative signs of which are correlated with inactivity of the prefrontal dorsolateral cortex, while an increased, more deeply localized, activity in the mesolimbic pathway may explain the positive signs. Several events occurring during pregnancy are likely to be involved in its genesis: hormonal supplementation by diethylstilbestrol, severe maternal denutrition, exposure to influenza virus, repeated psychological stress.
From multicentric studies and meta-analyses in the psychiatric literature, the risk of schizophrenia appears to be multiplied by two if pregnancy is complicated, mainly by diabetes, Rhesus incompatibility, bleeding, preeclampsia, premature rupture of membranes and preterm birth. When delivery is linked to an abnormal presentation or happens via a caesarean birth for acute foetal distress, the time when the first signs of psychosis appear seems to be earlier in adolescence or in early adulthood.
Cerebral imaging of schizophrenic patients shows ventriculomegaly and gray matter reduction, mainly in hippocampal volumes and in the dorsolateral prefrontal cortex. Similar alterations in the neuronal pathways have been experimentally reproduced in rats after repeated prenatal stress and perinatal hypoxia. A region on the distal portion of chromosome 1 has shown evidence for linkage to schizophrenia.
Exposure to diethylstilbestrol (DES) in the second trimester of pregnancy is likely to disrupt the laterality process, leading to an outstanding number of left-handed individuals, be they boys or girls. In the same way data from the literature suggest that people exposed to DES have a higher risk of presenting depressive signs. Nevertheless it may not be the only cause, since it is obvious that the gynecological troubles which required hormonal prescription may have affected the course of pregnancy. Katz et al. reported a higher risk of psychosis after the mother took DES about four cases: DES doses varied from 7 to 12.8 g, but two pregnant women out of four also received progestatives (total dose of 1.950 mg of medroxyprogesterone to 3.600 mg of progesterone).
Therefore, a two factor model seems to be able to explain the onset of schizophrenia in which obstetrical complications may interact with a genetic liability and in which the consequences of hypoxic events may lie on a continuum ranging from cerebral palsy in some children to subtle cognitive and behavioural disturbances in others.
- Obstetrical complications and subsequent schizophrenia in adolescent and young adult offsprings: is there a relationship?, European journal of obstetrics, gynecology, and reproductive biology, NCBI PubMed, PMID: 15140504, 2004.
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