Decision making under uncertainty and mood induction: further evidence for liberal acceptance in schizophrenia S. Moritz 1 *, R. Veckenstedt 1 , S. Randjbar 1 , B. Hottenrott 1 , T. S. Woodward 2,3 , F. V. v. Eckstaedt 1 , C. Schmidt 1 , L. Jelinek 1 and T. M. Lincoln 4 1 University Medical Center Hamburg-Eppendorf, Hospital for Psychiatry and Psychotherapy, Hamburg, Germany 2 Department of Psychiatry, University of British Columbia, Vancouver, British Columbia, Canada 3 Department of Research, BC Mental Health and Addictions Research Institute, Vancouver, Canada 4 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 11 November 2008 ; Revised 12 March 2009 ; Accepted 18 March 2009 ; First published online 11 May 2009 Key words : Cognition, decision making, jumping to conclusions, mood, mood induction, schizophrenia. Introduction Historically, schizophrenia has been regarded by many as ‘ utter madness ’ not amenable to understand- ing. Although this view has faded over the years and psychological treatments are being increasingly im- plemented (Bechdolf et al. 2006 ; Rollinson et al. 2007), the implications of this view continue. Schizophrenia patients, even if they have additional psychosis- unrelated severe psychological problems such as social phobia, are often deprived of psychotherapy. Treatment in many hospitals is confined to the ad- ministration of drug and occupational therapy. This is troubling because, notwithstanding the undoubtedly beneficial effects of neuroleptics on delusions, many patients show little or no symptom improvement un- der drugs and, even in the new era of atypical neuro- leptics, medication non-compliance remains a serious problem (Lieberman et al. 2005 ; Voruganti et al. 2008). Cognitive behavioural therapy (CBT) and, more re- cently, metacognitive training for psychosis have been found to yield surplus effects on symptomatology over the effects of antipsychotics (Zimmermann et al. 2005 ; Moritz & Woodward, 2007 ; Lincoln et al. 2008 b). However, such approaches are mostly implemented within a research context and not routine practice (for factors impeding the dissemination of psychological treatment, see Tarrier, 2005). The renewed interest in psychological treatments of schizophrenia is partly due to findings on cogni- tive biases associated with the disorder ; that is, * Address for correspondence : Professor S. Moritz, University Medical Center Hamburg-Eppendorf, Hospital for Psychiatry and Psychotherapy, Hamburg, Germany. (Email : moritz@uke.uni-hamburg.de) Psychological Medicine (2009), 39, 1821–1829. f Cambridge University Press 2009 doi:10.1017/S0033291709005923 Printed in the United Kingdom ORIGINAL ARTICLE