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Psychiatric Characteristics of Homicide Defendants
Martone CA, Mulvey MD, Yang S, Nemoianu A, Shugarman R, and Soliman L.

Most studies on mental disorder rates among perpetrators have been conducted in Europe, and have shown a higher occurrence of disorders in homicide offenders than in the general population. However, the applicability of these results to the US population is questionable. In addition, the results of past US studies on the psychiatric characteristics of offenders have been shown to vary considerably depending on the sample chosen and the sources of diagnostic information.

A study by Drs. Christine Martone, Edward Mulvey and colleagues is the first to provide a view of the relationship between psychiatric disorders and homicide in a comprehensive US sample unaffected by referral bias. The sample consisted of defendants who were charged with homicide in an urban US county between 2001 and 2005, and who received a psychiatric evaluation after arrest. Demographic, historical and psychiatric variables, as well as offense characteristics and legal outcomes were described. Bivariate analyses examined differences by age group and by race, and logistic models examined predictors of multiple victims, firearm use, guilty pleas, and receipt of a guilty verdict.

The results showed 58% the sample to have at least one Axis I or II diagnosis, which greatly exceeds the 25% rate found in the general US population. Axis I or II diagnoses were more common (78%) in defendants over 40 years old. Although 37% of the sample had prior psychiatric treatment, only 8% of the defendants with diagnosed Axis I disorders had outpatient treatment within three months preceding the homicide. In exploratory analyses, psychiatric factors did not predict multiple victims, firearm use in the crime, or a guilty verdict.

The rate of prior treatment observed in this sample raises issues relevant for mental health policy. Results showed that few homicide defendants were in psychiatric treatment at the time of the crime, suggesting limited opportunities for prevention by mental health providers and highlighting the need for enhanced engagement of high risk individuals into care (especially during times of emotional crisis) if mental health care providers expect to have an impact on serious violence.

Contributors:
Christine A. Martone, MD; Edward P. Mulvey, PhD; Suzanne Yang, MD; Layla Soliman, MD (Department of Psychiatry, University of Pittsburgh)

Andrei Nemoianu, MD (Hennepin County Medical Center, Minneapolis)

Ryan Shugarman, MD (Georgetown University Hospital and Saint Elizabeths Hospital, Washington, DC)

The results of this investigation were published in The American Journal of Psychiatry. Click here for a link to the abstract.