A randomized experimental investigation of reasoning training for people with delusions.

The present study aimed to investigate whether a brief reasoning training module changes the "jumping to conclusions" data gathering bias in people with delusions. A secondary aim was to examine whether improvements in reasoning would lead to greater flexibility in thinking about delusions. It was found that people with delusions and a diagnosis of schizophrenia (n = 34) requested less information on a reasoning task compared with a nonclinical control group (n = 34). The clinical group was then randomly allocated to a session of reasoning training or to an attention control condition. Following training, participants showed a significant increase in data gathering, and a small number reported more flexibility and less conviction in their delusions, although this finding was not significant. The presence at baseline of an extreme reasoning bias moderated the effect of training. The study provides further confirmation of the jumping to conclusions bias and shows that data gathering can be improved, though the severest form of the bias is resistant to change. It is recommended that lengthier, delusion-related reasoning packages be developed and evaluated.