Previous research showed that there is an association between persecutory delusions and inpatient aggression. However, it is not clear why some persons act upon their delusions with aggression. Research showed that persons with persecutory delusions have higher levels of delusional distress resulting from these delusions. This may explain why some persons act upon their delusions. Persecutory ideations lead to ideational distress which in turn can lead to aggression. The main aim of the present study was to test whether persecutory ideations have an indirect effect on inpatient aggression through delusional distress. The sample of the study consisted of 44 male inpatients from different general psychiatric inpatient wards. Results showed that the effect of persecutory ideations on inpatient aggression was partly explained by the level of delusional distress. Insight in the theory of acting upon delusions can be obtained by acknowledging this role of delusional distress in the relation between persecutory ideation and inpatient aggression. Early diagnosis of persecutory ideations and experienced delusional distress can be used in risk assessment of inpatients. Early interventions to reduce delusional distress, such as cognitive behavioral therapy, may prevent inpatient aggression. (C) 2012 Elsevier Ireland Ltd. All rights reserved.