Background : crimes committed by psychotic patients are common events. Schizophrenic and bipolar disorder are two important categories in psychotic patients who committed crimes during the acute phase of their disorder. This study was performed to evaluate the kind and comparison of crimes between these two groups of patients.

  Methods : In this cross-sectional study, 100 patients diagnosed with schizophrenia and bipolar disorder who had showed violence and referred to the department of forensic psychiatry in Legal Medicine Organization of Iran, were studied from April 2007 to April 2008. History taking & diagnosis based on DSM- IV-TR diagnostic criteria was done. The information was recorded in the questionnaire.

  Findings : In this study, 100 patients with schizophrenia and bipolar disorder were evaluated. 60 patients with schizophrenia and 40 patients with bipolar disorder were being evaluated in terms of sex, marital status, age, education level, type of offense, previous offenses, duration of illness, psychotic protests and history of alcohol, drug and psychotropic substances abuse. In terms of using psychotropic substances, psychotic protests and crime instrument, there were significant differences between patients with bipolar disorder and schizophrenia.

  Conclusion : The crime rate is much higher in patients with bipolar disorder than schizophrenia. Crime rates in these patients were higher in men, single and under graduate educationed. Most patients had no intention to commit a crime and it was based on their illusions. There was no significant difference between intention to commit a crime in two groups of patients. Most of these patients, especially schizophrenic group had a history of crime and first-degree relatives were harassed more. Single males who were under graduate and suffered from bipolar or schizophrenic disorders, should be at special attention in terms of committing a crime. It also seems that teaching patients with schizophrenia who have a history of crime commitment and their families, could be effective in reducing crimes.