Introduction
Schizophrenia is a very complex clinical picture, the exact causes of which have not yet been clarified. There are various attempts to explain the development of manifest schizophrenia. The most important model is the stress-vulnerability-coping model.
It states that before the onset of schizophrenic symptoms there is a susceptibility to schizophrenia. Thus, stress can trigger schizophrenia in the affected person because the so-called coping mechanisms are not sufficient. Coping means the ability to handle and process stressful situations.
What are the different causes of schizophrenia?
The exact causes are unknown, and a large number of individual factors are assumed to interact to trigger schizophrenia. Causes that can contribute to the development of schizophrenia include
- Genetic predisposition: the probability of schizophrenia is dramatically increased in children of schizophrenic parents. However, most new cases occur in patients who have no family history of schizophrenia.
- Changes in the brain: Changes in the limbic system, which is responsible, among other things, for processing emotions, have been observed in some people with schizophrenia.
- Biochemical changes: Our body is dependent on various substances to function correctly.
Especially the brain is dependent on a balance between the different messenger substances. In schizophrenia, irregularities have been found, especially in one messenger substance, dopamine.
Statistically, children of parents with schizophrenia are more likely to develop schizophrenia than those of the general population. The general population is about 1% more likely to have schizophrenia in children, 5 to 10 times more likely to have one parent with the disorder, and about 40 to 50 times more likely to have two parents with the disorder.
Twins are also at higher risk for the other child if one of them has schizophrenia. However, no alteration of a particular gene has yet been shown to explain the triggering of schizophrenia. At present, therefore, one can only speak of a statistically increased probability in first-degree relatives.
Although this strongly suggests a genetic component, about 20% of those with schizophrenia have a family member who also has schizophrenia. Various structural changes have been found in the brain that may partially explain the symptoms of schizophrenia. To determine this, a very large number of healthy people were compared with an equally large number of people with schizophrenia and the structural changes were statistically analyzed.
In the process, specific changes in certain areas of the brain of the patients were determined. Biochemically, the most widespread hypothesis is the dopamine hypothesis. Dopamine is a neurotransmitter that transmits signals to neurons (nerve cells) and in this way controls many processes in the brain.
In the past, it was assumed that a simple excess of the neurotransmitter dopamine leads to schizophrenia. From this assumption, we have now moved on to a much more complex variant. There are several “dopamine networks” in the brain. In schizophrenia, there is an imbalance in the distribution of dopamine and thus certain areas of the brain are oversupplied with dopamine and other parts are lacking. Other neurotransmitters involved are probably glutamate and serotonin, which influence information processing in the brain via various receptors.
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