Background: Sexual homicides - and particularly offenders with multiple victims - receive much attention in the general public as well as among forensic experts. The aim of this study was to assess psychiatric disorders in a large sample of sexual murderers and to identify disorders related to multiple sexual homicides.
Sampling and methods: Psychiatric court reports from 20 German forensic psychiatrists on 166 men who had committed a sexual homicide were evaluated for psychiatric disorders according to DSM-IV, including standardized instruments for personality disorders (criteria from the Structured Clinical Interview) and psychopathy (Psychopathy Checklist-Revised). Offenders with a single sexual homicide victim (n = 130) were compared to those with multiple victims (n = 36).
Results: High lifetime prevalence rates were found for substance abuse or dependence, paraphilias (especially sexual sadism), sexual dysfunctions and personality disorders (especially antisocial, borderline, sadistic and schizoid). In the multiple sexual murderer group sexual sadism, voyeurism, sadistic, antisocial and schizoid personality disorders were more frequent than in the single-victim group; none of the multiple offenders was diagnosed with a mood disorder.
Conclusions and limitations: Multiple sexual murderers are characterized by disorders in three major psychopathological domains: sexual as well as 'character' sadism, antisociality and schizoid personality. A thorough diagnostic evaluation of Axis I as well as Axis II disorders should be part of risk assessments in sexual homicide perpetrators. Although the study was a retrospective investigation on psychiatric court reports, the size of the sample and consistency with results from previous studies give confidence that the identified group differences are unlikely to be due to methodological limitations.