Dimensions of delusional experiences and their value as predictors of long-term outcome

Delusions are categorized as present or not in classificatory systems, but can fluctuate in intensity over time. They are sometimes difficult to describe, and might be better conceptualized as continuous on a number of dimensions. The predictive value of dimensional ratings of delusions was studied.

Out of 180 first-episode psychotic patients who had been personally followed up after 30 years, a subsample of 41 was randomly drawn, 21 of the 180, 10 of those with GAS scores of 70 or more, and 10 of those with GAS scores of 30 or less at follow-up. They represented three different groups - a good outcome (n = 17), an intermediate outcome (n = 12), and a poor outcome (n = 12) group. Based on case histories at first presentation, scores on the Dimensions of Delusional Experience Scale were recorded.

Poor compared to good outcome patients had delusions at index admission characterized by more conviction, extension, disorganization, bizarreness and pressure. Intermediate outcome patients had scores in between, but closer to the poor outcome group.

Dimensional rating scales for assessing delusions might have predictive power, and consequently they should be used in future research, and if replicated these findings might have clinical implications.