Schizophrenia is a mental illness in which an individual is unable to differentiate between fantasy and reality. This essay shall discuss the various theoretical causes of schizophrenia including; biological explanations such as genetics and chemicals in the brain, Freud`s psychodynamic explanations of the illness, and the family relationships that can worsen, or perhaps even cause schizophrenia.
Schizophrenia is quite a serious illness that affects about one per cent of the general population at some point in their lives, and may exhibit itself through a variety of symptoms. Around eighty per cent of people with the illness display ‘positive’ symptoms such as: delusions, hallucinations and disordered thinking; while the remaining twenty per cent suffer ‘negative’ symptoms such as: catatonic behaviour, loss of drive, and flattening of affect.
There has been a lot of research undertaken in to how our biology may cause us to develop schizophrenia, and it is now quite widely accepted that an individual’s genetic makeup may cause them to development schizophrenia, as the illness does have the tendency to run in families. Studies have shown that the more closely one is related to someone who already has the illness, the greater the risk of them also becoming ill. Non-identical (dizygotic) twins, who share fifty per cent of their DNA, have a seventeen per cent risk factor if their co-twin already has the illness; whereas identical (monozygotic) twins, who share one hundred per cent of their DNA, have a much larger risk factor of forty eight per cent.
The twin studies indicate that genetics do play a key role in the development of schizophrenia. However, as identical twins share one hundred per cent of their DNA, a twin should be at one hundred per cent risk, (they should ‘have’ the illness) if their twin has it. This suggests that there must be other participating causes that perhaps interact with our biology to bring on the illness. Furthermore, if genes were the sole cause of schizophrenia, it would not explain why the greater majority, (of around two thirds) of those with schizophrenia have no close relatives with the disorder.
Biochemical factors that may cause schizophrenia include the ‘dopamine hypothesis’. Dopamine is one of many neurotransmitters operating in the brain, and schizophrenics are believed to have an abnormally high number of dopamine receptor sites in the brain, thus resulting in more dopamine production, (class notes). Too much dopamine can be an effect of drugs, such as L-DOPA or amphetamines; such drugs worsen schizophrenic illnesses, and can cause schizophrenic type symptoms in otherwise healthy people.
There is supporting evidence for this hypothesis; for example, in the 1950s a selection of drugs known as anti-psychotics, were developed, which worked by reducing levels of dopamine in the brain. These drugs were very successful, and brought about substantial improvement in eighty per cent of schizophrenic patients, (those with positive symptoms).
The problems with these drugs include the fact that they do not work in twenty per cent of schizophrenics; those experiencing negative symptoms. However newer drugs, such as clozapine, have proved more successful in treating the disorder, (class notes). Anti-psychotic drugs have an effect on neurotransmitters other than dopamine as well; therefore it is unlikely that high dopamine levels alone cause schizophrenia. Another criticism of the dopamine hypothesis is that dopamine is not necessarily a ’cause’ of schizophrenia, but rather it could be an ‘effect’, or symptom of the disorder.
The ‘diathesis stress model’ explains how genetic and psychological factors may interact in the formation of schizophrenia. Some individuals are born with a genetic ‘pre-disposition’ to developing the illness, however the disorder will only present itself should it be ‘triggered’ by environmental factors that cause significant stress. This would help to explain why schizophrenia normally develops in the teens and early twenties; as this is usually a very stressful time for people.
Further biological explanations of schizophrenia include brain abnormalities; for example studies using computed tomography (CT) and magnetic resonance imaging (MRI) have shown that, in comparison with healthy people, those with schizophrenia have smaller brains and larger cerebral ventricles, (Stirling and Hellewell, 1999). Such abnormalities may be the result of poor brain development, or some sort of damage; such problems, it is believed, may lead to the onset of schizophrenia.