A large number of theories and hypotheses on the evolution of psychoses have been formulated. However, neither the biological nor the psychosocial research to date has been able to find a real cause applicable to all people. For this reason, today one assumes a so-called “multifunctional” cause, which means that various factors (biological and psychosocial) interact in the individual persons afflicted.
The currently best model on the evolution of psychosis is referred to as “vulnerability-stress-model”. This states that people with a possibly genetically induced predisposition to psychoses or rather other risk factors are particularly sensitive to stress situations such as puberty, school leaving examinations, falling in love, separation, overwork, holidays, moving house, marriage, loss or death of a closely associated person, pregnancy or other difficult life situation. Often, it is sensitive and creative people who are taken ill with a psychosis.
As a biological cause, metabolic disorders of so-called neurotransmitters (messenger substances) are associated with psychoses. Messenger substances are responsible for the flow of information between nerve cells. In the case of psychoses, it is assumed that among other things dopamine, serotonin and glutamate play a main role.
For the individual persons afflicted, these factors may be more or less significant. It is important therefore to record the development of the psychosis as completely as possible in the personal context and try to understand it in its circumstances. This is the basis of an individually integrated therapy of psychoses.
The “vulnerability stress model (vulnerability = the susceptibility to a disorder) means the susceptibility to react with psychotic symptoms in stressful stages of life. The susceptibility exists in all people; however, it is increased if various vulnerability factors come together. Stressful stages of life are for example puberty, school leaving examinations, marriage, loss or death of a closely associated person, pregnancy or other critical life situations. If these stresses coincide with vulnerability and insufficient coping mechanisms, in the event of a corresponding predisposition they can lead to psychotic symptoms. Despite this, through the protective effect of other factors (e.g. good social integration, good level of functioning, good coping skills), the onset of the psychosis can fail to materialize, so that a disorder is not inevitable.
a) Person with low vulnerability becomes ill in the event of high stress intensity.
b) Person with high vulnerability becomes ill already at a low stress level.
c) In the case of the same vulnerability the person can tolerate higher stress intensity at a higher protective level without falling ill.
As a biological cause, metabolic disorders of so-called neurotransmitters (messenger substances) are associated with psychoses. Messenger substances are responsible for the flow of information between nerve cells. In the case of psychoses, it is assumed that among other things dopamine, serotonin and glutamate play a main role. In this, various symptoms are put down to various disorders of dopamine at different places in the brain.
Vulnerability for the onset of a psychosis and accordingly schizophrenia can be favoured by various factors. In this, mostly a vulnerability factor alone is not sufficient to cause the psychosis. Rather, it is an interaction of various vulnerability and protective factors which cooperate in a certain manner. Risk factors for the onset of schizophrenia are for example:
| Type | Vulnerability factors |
|---|---|
| Clinical |
|
| Behaviour-related |
|
| Environment-related |
|
| Anatomically / neuro-anatomically |
|
| Chemical |
|
| Genetic |
|
| Motor |
|
| Perceptive-cognitive |
|
| Neuropsychological |
|
