Evidence for a relationship between the duration of untreated psychosis and the proportion of psychotic homicides prior to treatment

Background: Recent studies of homicide during psychotic illness have shown that the risk of homicide is greatest during the first episode of psychosis. It is also possible that the proportion of patients who commit homicide before they receive effective treatment may be associated with the length of time they were unwell. We aimed to establish whether there was an association between the average duration of untreated psychosis and the proportion of homicides committed during the first episode of psychosis in the same countries. Methods: Systematic searches of published studies of homicide in psychosis and the duration of untreated psychosis were conducted. The results were combined to examine the relationship between the reported delay in receiving treatment and the proportion of homicides committed before initial treatment. Results: We found 16 studies that reported the proportion of psychotic patients who committed homicide prior to treatment. The proportion of first episode patients ranged from 13% to 76%. We were able to match 13 of those studies with DUP studies from the same country. Longer average DUP was associated with a higher proportion of patients who committed homicide prior to receiving treatment. Conclusions: The possibility that the proportion of patients who commit homicide before receiving treatment may be related to the average treatment delay in the region that the homicide occurs needs to be examined using a case controlled design. If this finding were confirmed, then any measure that reduced the delay in treating emerging psychosis would save lives.