en پژوهشي Original Research Articles <p style="text-align: justify;"><strong>Objectives:</strong> New cognitive theories of delusions have proposed that deficit or bias in inference&nbsp;stage (a stage of normal belief formation) is significant in delusion formation. The aim of this&nbsp;study was predicting the severity of delusions based on jumping-to-conclusion bias in patients&nbsp;with schizophrenia.<br> <strong>Methods:</strong> The sample consisted of 60 deluded patients with schizophrenia who were selected&nbsp;from the Ebnesina and Razi hospitals in Shiraz using convenience sampling method. The&nbsp;Similarity Task was used to measure the jumping-to-conclusion biases.<br> <strong>Results:</strong> Its results have shown that the jumping-to-conclusion biases could predict a great part&nbsp;of the variance of delusions.<br> <strong>Discussion: </strong>These results generally indicated that the jumping to conclusion biases may&nbsp;provide a more useful explanation for the delusion formation.</p> Jumping–to-conclusion bias, Delusion, Similarity task 69 73 http://irj.uswr.ac.ir/browse.php?a_code=A-10-201-12&slc_lang=en&sid=1 Zahra Saffarian saffarian.psy@gmail.com Yes Department of Clinical Psychology ,University of Social Welfare and Rehabilitation Sciences, Tehran, Iran. Mohammad Ali Goodarzi No Department of Clinical Psychology, Faculty of Education and Psychology, Shiraz University, Shiraz, Iran. Maryam Abbasian No Department of Clinical Psychology, Sari Branch, Islamic Azad University of Sari, Sari, Iran. Javad Molazadeh No Department of Clinical Psychology, Sari Branch, Islamic Azad University of Sari, Sari, Iran. Habib Hadianfard No Department of Clinical Psychology, Sari Branch, Islamic Azad University of Sari, Sari, Iran.