Vulnerable individuals

Cullberg has presented a model to describe the risk of developing a psychosis. The model is described in detail in his latest book on psychosis. The risk of developing a schizophrenic psychosis is described as a vulnerability, which can be specified into three different categories: genetic vulnerability, disturbances in neuronal development and disturbances during the upbringing. If an individual is exposed to two factors, e.g. both a genetic vulnerability and disturbances during the upbringing, he or she is at greater risk of falling ill as compared to a person exposed only to one risk factor. By the same token, individuals exposed to all three risk factors are at the highest risk of developing a psychosis. However, Cullberg states that "only" presence of mental problems during the upbringing is not a cause for schizophrenia. Rather, it is the cause of non-psychotic personality disorders.

A particular kind of vulnerability often give the same symptoms
According to Cullberg, individuals with a particular kind of vulnerability often have the same kind of symptoms. One example is those with a disturbance in the neuronal development; these individuals often have difficulties in using language and expressing emotions. Schizophrenia is however a very heterogeneous disease, where symptoms and disturbances can take many expressions.

- For now we have to consider it as a hypothesis, which not yet has been proven. The future might bring increased knowledge and insight. Research might give us new information, enabling the doctors to understand by the symptoms which type of vulnerability the patient has.

Opportunity to provide support to the strong part of life
According to Cullberg, the vulnerability model not only offers an explanation to why a patient's life develops in a certain direction. The model also opens for an opportunity to provide support to the strong and healthy parts of a patient's life.