Jumping to conclusions and paranoid ideation in the general population.

An association of a 'jumping to conclusions' (JTC) reasoning style and delusions has been repeatedly found. The data-gathering bias has been particularly implicated with higher levels of delusional conviction in schizophrenia. For the first time the symptom, psychological and social correlates of jumping to conclusions are examined in a large general population sample. This is based upon the recognition that delusional ideation in non-clinical populations is on a continuum of severity with delusions in psychosis. Two hundred individuals completed a probabilistic reasoning task and assessments of paranoid ideation, intellectual functioning, affective symptoms, anomalies of experience, cognitive flexibility, illicit drug use, social support, and trauma. The jumping to conclusions reasoning bias was found in 20% of the non-clinical sample. JTC was strongly associated with higher levels of conviction in paranoid thoughts and the occurrence of perceptual anomalies, but not with the presence of affective symptoms. The results indicate that jumping to conclusions is a reasoning bias specifically associated with levels of delusional conviction, and is not a product of generally high levels of distress and affect. The association of jumping to conclusions with the types of anomalies of experience seen in psychotic disorders is intriguing, and consistent with recent dopamine dysregulation theories and the importance of reasoning to perception. The study is a further illustration of the need to consider the dimensions of delusional experience separately.