Homicidal behaviour among people with avoidant, dependent and obsessive-compulsive (cluster C) personality disorder

Despite a growing forensic psychiatry literature, no previous study has examined in detail homicidal behaviour among offenders with cluster C personality disorders - the avoidant, dependent or obsessional personality disorders.

This study aims to compare homicide offenders with cluster C personality disorders with those with other personality disorders on criminal history, offender-victim relationship and post-offence reaction variables.

The sample was drawn from all Finnish homicide cases of 1996-2004 for whom a forensic psychiatric evaluation had been conducted. Data were extracted from forensic psychiatric and crime reports.

In a nationwide sample of 593 homicide offenders, 21 had at least one cluster C personality disorder. These offenders had significantly shorter criminal histories than the others. Offender-victim relationship did not differ between the groups, but confession to the crime and feelings of remorse were more common among people with cluster C disorders. In addition, compared with other personality disorder clusters, co-morbid depression was more common.

Cluster C personality disorders are rare, but not nonexistent, among homicide offenders. Observed differences in their backgrounds and post-offence behaviours indicate that they may have special needs.