Schizophrenia is a common form of mental disorder, effecting 40-50% of psychiatric patients. Symptoms include hallucinations, delusions and disturbance of thought. Although sufferers do suffer a split in their mind- from themselves and the world around them, schizophrenia must not be confused with multiple personality disorder. It is the most serious of disorders in both ICD-10 and DSM-IV and both recognise the four different types of schizophrenia.

Each school of psychology has a theory for the aetiology of schizophrenia. The two main areas of thought to what causes the disorder are biological factors and environmental factors.

The biological approach is supported by the medical model in three sectors- the biochemical influence, the genetic influence and the neurodevelopment influence.

The biochemical theory proposes that schizophrenia be caused by chemical imbalances in the brain which, in turn are caused by an excess of the neurotransmitter- dopamine. There is evidence to support this claim. Firstly, post-mortem examinations of schizophrenics do tend to show high levels of dopamine, as found by Iverson in 1979. The problem w

The other type of study to prove the genetic theory is adoption studies. Heston has studied adopted children born to schizophrenic mothers but raised by non-schizophrenic parents and compared them to children raised by their biological, non-schizophrenic parents. The results were that 10% of the adopted children suffered with schizophrenia and none of the biologically raised children suffered. Kety et al, 1968 showed that there are many flaws in an environmentalist's view of schizophrenia- In Denmark, a list was compiled of adopted children and whether they were or were not schizophrenic. The rate was low in both groups but of the children that were schizophrenic- 21% had schizophrenic, biological mothers. This suggests that schizophrenia is genetic. An environmentalist would believe it was how the children were brought up in their surrogate families that would determine whether or not they ever suffered.

Strole et al blame poverty, he found that the highest rates of schizophrenia are in inner-city areas and is supported by Clark who found a positive correlation between schizophrenia and low status jobs. In this case it could be the fact that a person is schizophrenic which is stopping them getting a high status job, not vice-versa. Clark uses a correlation, which are often put down to coincidence rather than fact.

The genetic theory appears to carry more weight than the other biological theories. A person has a 1in a 100 chance of becoming schizophrenic, if one parent has schizophrenia then the chances increase to 1 in 5 chance and if both parents have had schizophrenia the likelihood further increases to a 1 in 2 chance. There has been extensive research on twins and adoption studies.

Most research has been in the medium of concordance rates between identical (MZ) twins and between non- identical (DZ) twins. The first of these tests was carried out by Kallaman in 1938, he found that MZ twins had concordance rates of 86.2% and DZ twins had rates of 14.5%. This makes sense as identical twins share the same, identical genes. However, he has been heavily criticised, the experiments were carried out long before ICD and DSM were introduced, therefore subjects may not have bee correctly diagnosed. There was also no scientific way for Ka

Some common words found in the essay are:
DSM-IV ICD-10, Osmond Smythies, ICD-10 DSM-IV, Self' Laing, RD Laing's, Gottesman Shields, Schizophrenia Schizophrenia, MZ DZ, LSD L-dopa, ICD DSM, et al, dz twins, genetic theory, mz twins, adopted children, concordance rates, schizophrenic behaviour, non-schizophrenic parents, children suffered, cause disorder,
Approximate Word count = 1521
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