DESCRIBE AND EVALUATE TWO EXPLANATIONS OF SCHIZOPHRENIA
There is a great deal of evidence supporting a genetic link with this condition. If this were so, the predisposing gene would be passed down though generations, giving them the same likelihood of developing it. Kendler et al 1985, showed that first degree relatives of those with schizophrenia are 18 times more likely to be affected than the general public. In a later study within a county of Ireland they found familial link, more so in siblings than with parents. This study was of a specific location and therefore could not be generalized to other populations. It also relied heavily on interview data, which may often be inaccurate. They were also conducted retrospectively, which produces less reliable data than from a longitudinal study.
Eliminating some of these problems, the Copenhagen high-risk study was carried out, following 207 children aged 10 to 18 years at the start, all with schizophrenic mothers. They were followed until the mean age was 42 and results, published by Parnas et al, showed that 16% had been diagnosed as schizophrenic, compared to 2% of a matched control group. This strongly supported a genetic link but because the offspring share the same environments with the parents, environmental influences have not been eliminated. The Israeli high-risk project attempted to separate genetic and environmental factors. This showed that even when separated from their parents and living in the same environment as a control group, the high-risk children are more likely to develop schizophrenia. The children’s age at the beginning of this study was up to 14 years. It could be argued that some children could have been affected in their pre-Kibbutz years.
Children with schizophrenic mothers, who had been adopted by the age of 4, were studied by Tienari in The Finnish Adoption Study. He found that 7% of them developed the condition compared to 1.5% of the control group. This offers support for the genetic theory but it could still be argued that their first four years with their mother affected their future health.
More conclusive evidence could come from those sharing identical genes. Twin studies have also supported the genetic link. Gottesman 1991, summarised many studies of MZ and DZ twins with one diagnosed as schizophrenic. He concluded that the concordance rate for MZs is about 48% and only 17% in DZs. This indicates a large genetic element but no study had revealed a 100% concordance in MZs, suggesting an involvement of environmental influences. The problems with these studies include, only small sample groups being available and the criteria for diagnosis changing over the years.
There have been a variety of psychological explanations of schizophrenia. In 1948 Fromm-Reichman proposed that schizophrenia was caused by a dysfunction of communication within the family. They termed these as Schizophenogenic families. They have cold mothers, incompetent fathers, high emotional tension and have many conspiracies. This theory is supported Tienari who assessed the quality of parenting during his adoption study, and found that all who developed schizophrenia were from families rated as disturbed. This was echoed in the Israel high-risk study by Marcus. He found that all the schizophrenics had poor parenting ratings, regarding hostility, inconsistency and over-involvement. This alone cannot explain why many children of these families did not develop the condition. The studies were also conducted retrospectively, which means that the person’s mental disorder may have already disrupted the families functioning. The dysfunction could therefore be the effect rather that the cause. By the 1970s the family, and the emotions they expressed, were studied for their role in the course (relapse rate), not cause of schizophrenia. In 1976 Vaughn and Leff proposed the EE model which linked overcritical and over-concerned families with high relapse rates.
Other family related explanations include the double-blind theory. Bateson et al 1956, suggested that continuous conflicting messages from parents lead to confusion, self-doubt, withdrawal and eventually schizophrenia. The dynamics of marriages have also been but forward as a cause of schizophrenia. Lidz proposed that a skewed marriage, with one parent dominating and being inconsiderate to the family can lead to this condition. A schismatic marriage has also been linked, where both feuding parents use the child as a pawn. The findings leading to these theories could not be successfully replicated and there popularity declined.
It has been proposed that social status can determine vulnerability to schizophrenia. The social causation hypothesis suggests that members of lower social classes have more stressful lives with less support or compensations, and are therefore more vulnerable. Alternatively, the social drift hypothesis points out that schizophrenia leads to reduced social status, which would explain the higher incidence in lower social classes.
Behaviourists believe that displaying schizophrenic symptoms can for some people be rewarding. This can be in the form of escape to a more peaceful inner world, or by receiving attention and sympathy following bizarre behaviour. Once labelled in this way they will model their behaviour on learned stereotypes and conform to the label. Scheff proposed that mental illness is no more than a “dustbin category” for all behaviour that cannot be explained. In support of this theory it has to be acknowledged that “normal behaviour” varies across time and cultures, and the criteria for schizophrenia has been dynamic. On the other hand it cannot explain the physiological differences, such as larger brain ventricles, the dopamine hypothesis and abnormal brain structure & metabolic activity. It also offers no explanation of why it affects some but not others.
Many aspects of the genetic and psychological models have been brought together in the diathesis-stress model. This proposes that some people inherit a genetic vulnerability towards schizophrenia, which may or may not develop, depending on whether the environment is supportive or stressful. Most of the research findings would support this model which is still popular today.
