Schizophrenia is one of the most complex and difficult mental diseases ever known; it is difficult to diagnosis and even more difficult to know its causes. Theorists and scientists have mentioned different reasons and causes behind this disease and these hypotheses have been dramatically changed throughout the history. What is schizophrenia and what causes this disease? Is there a reason or a range of reasons behind it? Is the causes are genetic, biochemical, behavioural, or environmental? In order to find a reliable or at least an acceptable answer to this question, this short essay tries to analyse different theories and hypotheses about schizophrenia.
Schizophrenia is a severe disease of brain; it is common to a degree as it affects 1% of population with similar numbers of males and females. It affects poor more than rich people. It is not a split personality as it was thought, but it is a split from reality. It is a chronic disease and even hard to treat, however it is controllable with medications nowadays. As there is not a special known cause for schizophrenia, many suggestions and hypotheses have been made throughout the history, starting with myth and magic and continuing with the latest technology of the 21st century.
Although there are still mysteries surrounding schizophrenia, it is not a new illness. Symptoms relating to schizophrenia have been noted since the age of antiquity. A popular belief was that strange behaviour was a result of possession by the devil or assaults from the gods for immoral behaviour. [History of schizophrenia, online]
Patients of schizophrenia are diagnosed with positive and negative symptoms: positive symptoms are hallucinations, delusions and thought disturbances, and negative symptoms are loss of energy, lack of expressed emotions and prevention from talking, especially in the sever stages. However it is not easy to diagnose a patient for schizophrenia at the first place because:
It usually comes on very slowly and so the personality of the person developing it changes very slowly. Often the patient is quite normal. It is therefore difficult to detect disease at such times. Sometimes when the disease is quite advanced and the true personality of the patient quite overlaid by the ill personality, the ill personality may be mistaken by doctors as the true personality. [Schizophrenia Association of Great Britain, online]
Some scientists argue that the cause of schizophrenia is genetic. They have carried out researches on twins and collected useful data. The US Surgeon General's Report on Schizophrenia found out that there are great possibilities for identical twins more than fraternal twins and coming down to lower possibilities to end in 1% in general population. [See Appendix 1]
The same report gave further details to emphasis the genetic cause of schizophrenia by saying:
Family, twin, and adoption studies support the role of genetic influences in schizophrenia. Immediate biological relatives of people with schizophrenia have about 10 times greater risk than that of the general population. Given prevalence estimates, this translates into a 5 to 10 percent lifetime risk for first-degree relatives (including children and siblings) and suggests a substantial genetic component to schizophrenia [US Surgeon General's Report on Schizophrenia (2002) online]
However the available data cannot suggest that the cause of schizophrenia is wholly genetic, if it was so the rate should be 100% in identical twins, as they have the same genes. Holding a gene may put somebody in danger but it is not the only cause, as Turner said:
The diathesis stress model of mental illness suggests that inheritance can put people at risk; however, stress may also play a part. [Turner, 2003: 73]
The US Surgeon General's Report on Schizophrenia also mentioned other causes together with genetic causes for schizophrenia, however the main cause or the basic one is still genetic, as they argue:
Current research proposes that schizophrenia is caused by a genetic vulnerability coupled with environmental and psychosocial stressors, the so-called diathesis-stress model. Family studies suggest that people have varying levels of inherited genetic vulnerability, from very low to very high, to schizophrenia. Whether or not the person develops schizophrenia is partly determined by this vulnerability. [US Surgeon General's Report on Schizophrenia (2002) online]
However, the research in this field continues and still it is not clear either a single gene or a group of genes are responsible for this illness.
The chemical balance of the body suggests another hypothesis for the cause of schizophrenia. Biochemical theorists argue that a high rate of neurotransmitter dopamine is the cause of this disease. This argument comes after they have treated patients with Parkinson's disease by dopamine. They noticed that:
Drug treatments to increase dopamine levels in Parkinson's patients can have side effects similar to the symptoms of schizophrenia. [Turner, 2003: 73]
They have also noticed that the antipsychotic drugs which reduce the levels of dopamine can be used to reduce the symptoms of schizophrenia. They based their arguments on post-mortems which suggest that "schizophrenic patients have high levels of dopamine in their brains. Drug users who take amphetamines and cocaine have symptoms similar to schizophrenia, and these drugs are known to increase dopamine levels. [Turner, 2003: 73-74]
