a1 University Medical Center Hamburg-Eppendorf, Hospital for Psychiatry and Psychotherapy, Hamburg, Germany
a2 Department of Psychiatry, University of British Columbia, Vancouver, British Columbia, Canada
a3 Department of Research, BC Mental Health and Addictions Research Institute, Vancouver, Canada
a4 Department of Psychology, Philipps-University Marburg, AG Clinical Psychology and Psychotherapy, Marburg, Germany
Background Cognitive biases, especially jumping to conclusions (JTC), are ascribed a vital role in the pathogenesis of schizophrenia. This study set out to explore motivational factors for JTC using a newly developed paradigm.
Method Twenty-seven schizophrenia patients and 32 healthy controls were shown 15 classical paintings, divided into three blocks. Four alternative titles (one correct and three lure titles) had to be appraised according to plausibility (0–10). Optionally, participants could decide for one option and reject one or more alternatives. In random order across blocks, anxiety-evoking music, happy music or no music was played in the background.
Results Patients with schizophrenia, particularly those with delusions, made more decisions than healthy subjects. In line with the liberal acceptance (LA) account of schizophrenia, the decision threshold was significantly lowered in patients relative to controls. Patients were also more prone than healthy controls to making a decision when the distance between the first and second best alternative was close. Furthermore, implausible alternatives were judged as significantly more plausible by patients. Anxiety-evoking music resulted in more decisions in currently deluded patients relative to non-deluded patients and healthy controls.
Conclusions The results confirm predictions derived from the LA account and assert that schizophrenia patients decide hastily under conditions of continued uncertainty. The fact that mood induction did not exert an overall effect could be due to the explicit nature of the manipulation, which might have evoked strategies to counteract their influence.
(Received November 11 2008)
(Revised March 12 2009)
(Accepted March 18 2009)
(Online publication May 11 2009)
c1 Address for correspondence: Professor S. Moritz, University Medical Center Hamburg-Eppendorf, Hospital for Psychiatry and Psychotherapy, Hamburg, Germany. (Email: firstname.lastname@example.org)