A delusion can occur without other symptoms. Someone can imagine that he is being persecuted or that he is a powerful person. Delusions that trigger jealousy also occur.
Postpartum psychosis can be induced by hormonal changes after birth and is often reminiscent of schizophrenia or bipolar disorder. It is very rare, occurring only in around one in 500 pregnancies.
A completely different illness can also affect the brain – and thereby cause psychotic symptoms. Goitre, brain tumours, Huntington’s chorea, viral infection and AIDS are all examples of diseases that can have this effect.
Since these diseases normally can be diagnosed with the aid of physical tests, if they are the cause it is quickly apparent. Even so, of course, it may be hard to make a diagnosis, especially in the beginning. However, it is important to find out more about whether there is an underlying disease, since the treatment will the be a different one. If this other disease can be treated, the psychosis will ordinarily disappear.