To what extent is it possible to explain schizophrenia from a biological perspective?

The prevalence of schizophrenia is around 1% of the total population; however research has indicated the relatives of schizophrenia sufferers have an increased risk of developing the disorder. The main aim is finding has schizophrenia a biological predisposition? Do genes form a common characteristic in the prevalence of the disorder and how do environmental factors link in with the development of the disorder.
Given that Psychologists are now in agreement that schizophrenia is a result of interplay between biological predisposition and the environment that the sufferer is exposed to. It is clear that genetics plays a vital role in the development of schizophrenia and there is strong evidential links that people who have relatives diagnosed with schizophrenia have an increased risk of developing the disorder. Research presented by Gottesman (1991) illustrated the risks in developing the disorder by the relative closeness to someone who has been diagnosed as schizophrenic. From this research it suggests that if you have a parent that is diagnosed as schizophrenic then you have a 13% increased risk in development, this is a strong close link to the sufferer. The research also shows that the grandchild of a schizophrenic has a five per cent risk of developing the disorder, this strongly illustrates the closer the biological relationship the higher the risk.
Another key factor that has to be taken into account when working toward an understanding of schizophrenia and the genetic links involved with the disorder is twin studies. Research has been presented to highlight the genetic link via twin studies conducted by Gottesman (1991); it indicates that if one identical twin has schizophrenia then the other twin has a forty-eight per cent chance of development, whereas fraternal twins have a seventeen per cent chance of development. From this it is clear that the genetic argument for schizophrenia does hold some substance as identical twins share one hundred per cent of their genes and fraternal twins share fifty per cent. Furthermore it does not fully explain why fifty-two per cent of identical twins do not develop the schizophrenic disorder. It is evident that genes alone cannot account for schizophrenia there has to be a certain amount of environmental conditioning which triggers the disorder.
However the findings included in Gottesman’s (1991) research does not equate to the basis that schizophrenia is founded completely on genetics. Many related people share similar environments and the closer the relative the similar the environment. For this reason research was then conducted by Gottesman & Shields (1972) in finding; do genes have any influence as most twins grow up in a shared environment? Gottesman & Shields (1972) studied identical twins that had been raised in different environments and found that in seven out of twelve cases, the pair both suffered from schizophrenia. This research still does not fully explain the foundations of schizophrenia as many twins both shared the same paternal womb. Although they have been raised apart they still shared the womb for nine months and as the viral hypotheses would suggest if one twin suffered from a virus inside the womb then the other twin would also, thus leading to the development of schizophrenia in both twins.

Another key piece of research carried out by Kety (1988) compared adult’s suffering from schizophrenia that had been adopted as children, with their biological and adoptive parents. From the research conducted by Kety (1988), out of 5,500 people whom were adopted as children only 33 were diagnosed as suffering from schizophrenia, with 14% of the biological relatives diagnosed and a mere 2 % their adoptive relatives subject to the disorder. Kety concluded the prevalence of schizophrenia was ten times higher in genetic relatives than in adopted relatives. This suggests