Recovery From Schizophrenia: Psychiatry And Political Economy

204 THE INCIDENCE OF SCHIZOPHRENIAeducated in the earlier Taiwanese study could be due to a number of factors, butthey cannot be due to the drift of people with schizophrenia or at risk forschizophrenia into a different social stratum. People cannot change their caste,nor would they drift into higher education. Many of the studies are field surveysand, therefore, would not be influenced by differences between groups intreatment-seeking behavior. As we shall see shortly, however, changes inmaternal nutrition and fetal and neonatal health in response to changing socialconditions could produce this pattern through a neurodevelopmental effect.It seems likely that the occurrence of schizophrenia in the West increasedduring the nineteenth century and possible that it has peaked and has beendecreasing during the past four decades. In preindustrial settings the illness is moreprevalent in the upper castes and classes, but in the post-industrial West the illnessis more common in the poorer classes. Can we explain this pattern of occurrence?INDUSTRIALIZATION AND THE HAZARDS OFCHILDBIRTHObstetric complications are one of the contributory causes of schizophrenia. 33The risk of schizophrenia in people who suffer obstetric complications at birth hasbeen variously estimated to be in the range of one-and-a-half to three timesgreater than those who have normal deliveries. 34 Some researchers argue thatthose who develop schizophrenia following obstetric trauma tend to be peoplewithout a genetic vulnerability to the illness. 35 Others suggest the reverse—thatpeople with a genetic predisposition to schizophrenia inherit a nervous-systemfragility that renders brain tissue more sensitive to the effects of oxygendeprivation or intracranial bleeding. In the latter case, the combination ofgenetically based neural developmental abnormality and subsequent nerve tissuedamage leads to the development of the illness. 36 It is likely, in fact, that obstetriccomplications are a risk factor for people with or without a genetic vulnerabilityto the illness.In the general population, obstetric complications occur in up to 40 per cent ofbirths (the precise rate of occurrence depending on how they are defined). 37Because they are so common, they are responsible for a large proportion of casesof schizophrenia. According to one analysis complications of pregnancy anddelivery increase the prevalence of schizophrenia by 20 per cent. 38Changes associated with industrialization alter the risk of obstetric complicationsdifferentially in the various classes. For example, obstetric complications includeproblems with delivery caused by narrowing of the pelvic canal. A significantproportion of women with poor nutrition suffer from pelvic contraction due tochildhood rickets caused by vitamin D deficiency. Improvements in nutritionduring industrial development reach the upper classes first, but the first generationof women who gain this benefit are relatively small in stature and at risk for bonydeformities because, as children, their nutrition was inferior. Their children,however—the first generation to have better nutrition from the outset—are bigger.