Mood theme and bizarreness of delusions in schizophrenia and mood psychosis.

Narratives of the delusions of 83 schizophrenic and 55 nonschizophrenic psychiatric subjects were categorized as of one or more of 12 types. Narratives were also independently assessed along dimensional scales of bizarreness and mood theme. Schneiderian and grandiose types were found to be more common in schizophrenics and mood psychotics, respectively. Dimensional measures showed that the delusions of schizophrenics were more unlikely and that those of mood psychotics had a stronger mood theme. Regression analysis determined that Schneiderian delusions and a dimensional estimate of mood theme best differentiated schizophrenics from mood psychotics. Assessments along dimensions of other parameters, particularly those represented by Schneiderian delusions, may further discriminate the functional psychoses.