Critically Consider Biological Explanations of Schizophrenia Essay

1909 Words Mar 27th, 2006 8 Pages
The term ‘schizophrenia' covers a group of serious psychotic disorders characterised by a loss of contact with reality. It comes from two Greek words: schiz meaning ‘split' and phren meaning ‘mind'. DSM IV (1994) estimate that the occurrence rate of schizophrenia ranges from 0.2%-2.0% worldwide. There are two main explanations of schizophrenia: the biological explanations and the psychological explanations. In this essay I will critically consider the biological explanations. These include genetics, neurochemistry, brain structure and evolution. Genetic factors of schizophrenia can be explained using studies on twins and studies on family history. With twin studies researchers want to establish the degree of concordance. This is …show more content…
There was a large difference in the incidence of schizophrenia when they were adults between the two groups. The group with schizophrenic mothers were found to have a 10.3% chance of being schizophrenic and the group with non-schizophrenic mothers were found to have only a 1.1% chance of being schizophrenic.
Kety et al. (1978) examined early-age Danish adoptees matched on gender and age. 50% of these adoptees were diagnosed as schizophrenic and 50% were not. They found that the incidence of schizophrenia was greater among the biological relatives of those with schizophrenia than those without. This is expected if genetic factors are important. They also found that the rate of schizophrenia was no different for adoptive families who had adopted a child who became schizophrenic compared to those who had adopted a child that did not become schizophrenic. This therefore suggests that environment is of little importance.
However Kety et al.'s (1978) study is criticised due to the fact that they drew their adoptees from 1924-1947 and gathered their statistics from a time-span of over 70 years. This means that the uniformity of the diagnostic criteria must be queried due to the change in interpretations of symptoms.
Genetics can cause differences in brain chemistry and biochemistry may be important in the development and maintenance of schizophrenia. The dopamine