Intimate partner homicide-suicide (IPH-IPS) occurs when a person kills an intimate partner (eg, spouse, former spouse, dating partner, or ex-partner) and then kills themselves. When women die due to IPH-IPS during the childbearing years, ages 15 to 50, the event may leave a lasting and detrimental impact on the health and a potential for violence in any surviving children as well as a devastating impact on the family and community.1,2 Identifying the patterns associated with this problem is the first step in the recognition of risk factors and danger signs that may lead to early intervention and prevention of the devastating impact it has on families and society.
Hannah et al, 1998 noted that the average age of homicide-suicide (of both victim and perpetrator) was 32 and Bossarte et al, 2006 found that 62.5% of victims and 68.0% of perpetrators of homicide-suicide were aged 15 to 44.3,4 The exact rate of IPH-IPS is unknown because there are no national surveillance systems that track these events.5 Information concerning IPH-IPS has been gained through local or statewide research studies or as part of domestic or intimate partner violence fatality reviews. Among homicide cases studied, 18% to 40% were IPH-IPS.5–17
This report highlights findings from a population-based study of all IPH-IPS events among women aged 15 to 50 identified in Maryland from 1994 to 2003. The purpose of this study was to describe the temporal trends and the characteristics of both victims of the event. Understanding the characteristics of IPH-IPS in this population would add valuable information that may lead to the prevention of this devastating event.
MATERIALS AND METHODS
This study reviewed all cases of women aged 15 to 50 who were referred to the Maryland Office of the Chief Medical Examiner from January 1, 1994 to December 31, 2003. All associated cases were also reviewed. Inclusion criteria for this study were female age 15 to 50, manner of death homicide or suicide, intimate partner violence noted at the time of the incident and the case involved IPH-IPS.
Information in the record included race, marital status, age, manner and cause of death, autopsy findings (including toxicology), and notation of intimate partner violence and associated cases. This information was collected and analyzed. The notes recorded in the record indicating an intimate relationship between the victims was used to determine intimate partner status. IPH-IPS was defined as intent to commit homicide (1 or more), victim and perpetrator related by marriage, ex-marriage or current or prior dating relationship, and a completed suicide of the perpetrator within 1 week of the homicide.19 This definition included cases where there was an attempt to commit homicide but the attempted-homicide victim survived. Analyses were conducted using SAS 9.1 for Windows. IRB exemption for the study was obtained before data collection.
There were 679 homicides and 502 suicides among women aged 15 to 50 during the 10-year period. There were 229 (34%) intimate partner homicides where the woman was a victim of homicide and 71 (31%) were IPH-IPS. Seventy-five cases met the study criteria for the study. These cases included 71 (94.7%) female homicide/male suicide, 3 (4.0%) male homicide/female suicide and 1 (1.3%) male attempted homicide/female suicide (Table 1).
The annual age and gender-adjusted rate of IPH-IPS using 3-year rolling averages ranged from 0.44 to 0.59 per 100,000 women aged 15 to 50, and averaged 0.52 per 100,000 women aged 15 to 50 over the 10-year period (Fig. 1).
The ages of both males and females varied across all age groups. The mean age for females was 34.9 and 40.6 for males. About half of both females and males were white, within 5 years of the age of their partner, and married or separated. Most couples (88%) were of the same race. Eleven percent of the women were pregnant or within 1 year postpartum at the time of the incident and 93% of females died due to gunshot wounds (Table 1). There were no significant relationships between race and the age difference of the partners (data not shown).
There were differences in the ages of both males and females when comparing whites to nonwhites. The mean age of women was significantly different by race. The mean age for white females was 43.6 years compared with 32.8 years for nonwhite females (P = 0.035). A similar pattern was noted for males. The mean age for white males was 41.7 years compared with 31.1 years for nonwhite males (P = 0.021).
There were 8 women who were pregnant or had been pregnant in the past year who died due to IPH-IPS. Among the 4 women where marital status was known, women who were pregnant/postpartum at the time of their death were 4.0 (1.7–9.4) times more likely not to be married at the time of their death compared with nonpregnant/postpartum women. There were no statistical differences in the race of either victim, age of the male or age of the female among pregnant/postpartum versus nonpregnant women, however only 1 IPH-IPS occurred in white women (3.1%) compared with 7 (16.2%) in nonwhite women and all 8 IPH-IPS deaths among pregnant/postpartum women occurred in women under age 36. Of the 8 males who were victims of IPH-IPS, 6 were under 40 (Table 2).
Age difference was evaluated by subtracting the age of the female from the age of the male. The differences in age ranged from males who were 13-years younger than the female to 45-years older then her. The mean age difference was 5.5 with a standard deviation of 8.9 and a median of 4.0. There was a significant difference in the age difference depending upon the age of the male. Males who were under 40 were 10.5 (2.17–50.8) times more likely to be within 10 years of the female compared with males over 40 (Table 3).
Understanding the problem of IPH-IPS involves a more comprehensive assessment of both victims of this irreversible event including the circumstances leading up to and surrounding their deaths. There is a need for a national surveillance system that identifies IPH-IPS events and provides information on both victims that includes individual and relationship characteristics including personality traits, mental status, and prior relationship interactions so that a comprehensive investigation of the problem can be conducted.
This is the first study to evaluate IPH-IPS among childbearing women as a specific population and to include reports of pregnancy status. Prior studies of homicide-suicide that focused on female cases, did not report on age, race, marital status, or pregnancy status.8,11
The mean age for both victims and perpetrators in this study were similar to other studies that evaluated all homicide-suicide events or evaluated IPH-IPS in all age groups. Similar patterns were also noted for race and marital status.8,11,12,17 About half of all couples were white race and married and 92% of couples where the same race (Table 2). Nonwhite couples, were significantly younger compared with white couples. Of the female victims, 8 (11%) were either pregnant or within 1 year postpartum, higher than the proportion noted for intimate partner homicide.19,20
The annual age and gender-adjusted rate of IPH-IPS in this study averaged 0.52 per 100,000 women of childbearing age, higher than that noted in studies of all homicide-suicide events,5,21 indicating that this is an important group to evaluate in future studies.
Identification of IPH-IPS in this study used information noted in the medical examiner record for the woman, therefore cases may have been missed if a relationship between the victim and perpetrator was not identified in the record or the perpetrator committed suicide at a time and place separate from the homicide that was not noted in the record. In this study, 5 (5%) cases of homicide-suicide were excluded from the analysis due to a lack of information on intimate partner status, it is unknown how many cases were missed due to a lack of any notation of an associated case in the record. Although detailed searching was conducted to identify suicides following the homicide, the findings were limited by notation in the record of an associated case or other clues in the record indicating the perpetrator committed suicide.
A standardized method to link cases, including national surveillance is critical to identify the magnitude of this problem. An estimated one-third of all intimate-partner homicides of women in this age group end in suicide,17 national surveillance may find the proportion to be higher.
Prior reports described IPH-IPS victims as more often older, white and married and estranged from their partners.5,12,13,22–24 In this study, most couples in this study were married, the same race, within 9 years of each other and the mean ages for both victims and perpetrators were over 30, but there were significant differences in the mean ages of IPH-IPS victims and their perpetrators based on race.
Two new findings that were not reported in prior studies were noted. First, most women who were pregnant or postpartum at the time of the incident were not married and most of the incidents involving a pregnant/postpartum woman occurred among nonwhite couples. Second, the age difference of the couple was significantly different among couples with men under 40 compared with couples with men over 40. The differences in findings by race and pregnancy status and age difference may represent different contextual forces that lead to this devastating outcome, indicating the need for a broader approach to understanding this problem that addresses socioeconomic, psychological, and other cultural differences when developing interventions to prevent the progression of violence to this devastating outcome.
Lund and Smorodinsky (2001) stress that we know little about homicide-suicide in large populations including the risk factors for perpetrator suicide and the characteristics of perpetrators and their victims.12 The findings presented here represent a significant public health problem that has a unique pattern that appears different compared with other populations that have been studied. The occurrence of IPH-IPS has a low base rate, yet these irreversible outcomes are devastating and have lasting repercussions for the surviving children, families and communities.25
The author thanks TM for support, encouragement and contributions to this manuscript.
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