http://en.wikipedia.org/wiki/Delusion
Development of specific delusions
The top two 'Factors mainly concerned in the germination of delusions' are:1. Disorder of brain functioning and 2. background influences of temperament and personality[12].
Higher levels of dopamine qualify as a symptom of 'disorders of brain function'. That they are needed to sustain certain delusions was examined by a preliminary study on delusional disorder (a psychotic syndrome) which was instigated to clarify if schizophrenia had a dopamine psychosis [13] There were positive results - delusions of jealousy and persecution had different levels of dopamine metabolite HVA (which may have been genetic). These can be only regarded as tentative results; the study called for future research with a larger population.