This study represents one of the first to examine past year assault among a large consecutive cohort of medical and injured ED patients. This data suggest that a significant proportion of patients presenting to an inner-city ED have been involved in violence with a non-partner in the past year: 14% of all patients sampled and 21% of injured patients sampled. The prevalence of NPV found in this sample is higher than NPV prevalence found in community samples (e.g., 5.6%)58
and is equal to or higher than studies assessing past year IPV in the ED setting,59, 60
This data suggests that more patients who are experiencing NPV (42%) are experiencing both non-partner victimization and aggression than either type of non-partner violence alone (e.g., episodes of being the aggressor and
being the victim). Of note, however, is that the context in which the aggressive behaviors occurred was not assessed; it is not clear whether the aggression and victimization occurred with the same person, as part of the same conflict, or with different people. Further, there is no way to ascertain if the participant was acting in self-defense. Despite this, the correlates of victimization and aggression of violence are very similar, supporting the concept of the cycle of violence or bi-directionality (for review see Straus, 200761
or Daday et al. 200821
Although men reported higher rates of NPV than women, many women also reported violence (victimization and aggression) in non-partner relationships. Prior work suggests that patients who are experiencing NPV may also be experiencing violence in their intimate relationships.23, 62
The elevated prevalence of NPV found in this study suggest that the ED may be an ideal venue in which to identify and intervene with NPV, as is done routinely for IPV. For example, identification and intervention with men experiencing NPV may be protective in their current or future relationships, and advance intimate partner violence prevention efforts as well as decrease the individual’s future injury-related morbidity.
Although some research suggests that correlates of violence are similar for partner and non-partner violence (e.g., age, alcohol/drug problems, overall mental health),63
others note subtle differences in violence depending on relationship type, gender, and psychiatric status.62, 64
For example, prior research in substance use treatment settings and ED samples find that men report greater NPV than women.16, 31, 39
As noted by Graham and Wells (2003),65
male violence may be seen as more normative and acceptable than female violence in certain social settings (e.g., bars) and may also be related to concepts such as “face saving” and not wanting to “back down” from a violent confrontation, particularly when in the presence of others.
Although the temporal association of violence and the substance use reported in this study is not known, substance use and violence often co- occur in individuals, and often neither the violence nor the substance use are isolated events. Criminal justice data note that 5% of assailants were reportedly under the influence of drugs at the time of their crime.66
Findings indicated that a quarter of the participants noted that they have experienced fighting (relationship type not specified; non- partner, or partner) while using alcohol or drugs. These findings are in keeping with clinical and laboratory studies, which have generally found a relationship between physical aggression, alcohol, and cocaine.29, 33, 67, 68
More specifically, studies have demonstrated that alcohol and cocaine use are related to the frequency with which aggression occurs and the severity of the injuries sustained.69–73
There is evidence to suggest that the acute pharmacological effects of cocaine may increase aggressiveness.67
Non-ED studies have found evidence for acute cocaine consumption and aggression.29, 74
Marijuana use is also related to both aggression and victimization (for a review see Hoaken et al., 200375
); this association is likely due to contextual factors and self-selection/self-medication, as well as to marijuana withdrawal.76
Theories focusing on the relationship between alcohol and other drug use and violence highlight the role of a variety of risk domains, including acute intoxication effects, social/contextual factors (relationship type, partner/non-partner), and other individual difference factors (gender, depression).33, 77
In general, substance users (particularly cocaine users) are frequent victims of violence71, 78
and are at increased risk for injuries sustained while under the influence. The relationship of substance use and violence are unlikely to be solely explained by the pharmacology of the drug. The exacerbated rates of violence experienced by substance users are likely not solely related to the timing of intoxication, but rather to clustering of high risk behaviors in the individual. For example, obtaining and/or using illegal substances involve a social/environmental context with people and places where NPV is likely to occur. Baskin-Sommers (2006)79
have suggested that aggression may be partially explained by the tendency of drug users to become more exposed to and desensitized by violence due to interacting with individuals already immersed in a violent drug culture. Thus, there may be greater opportunities for users of illicit substances to be experience violence, regardless of whether they were intoxicated at the time of the occurrence of violence. These assertions require validation with studies using calendar approaches to tease out the influences of acute consumption and NPV.29, 74
To the best of our knowledge, this is the first ED study to disentangle cocaine and marijuana use in relation to NPV, as opposed to being combined into one “illicit drug” category, as well as to show an association of NPV (in both victimization and aggression) and use of prescription drugs. Future studies evaluating any prescription drug use the role of prescription drug misuse (and specifically opiate dependence), and the relationship of prescription use to other illicit drugs and NPV are needed to further evaluate this association.
The regression analysis shows that, accounting for other variables in the model, there is a pattern of increasing association of violence from any prescription drug use, to alcohol only, to marijuana, to cocaine users. The association of cocaine use in particular to both NPV aggression and victimization is highlighted in this data. Although this relationship may not be surprising, it highlights the need to address drug use in general, and cocaine use specifically among patients presenting with violence.
Finally, patients reporting NPV in this sample also report poor mental health, which was a strong marker of NPV, even when other demographic and substance use variables were considered. Studies of participants with substance use disorders found that for both men and women, psychiatric distress was associated with aggression and victimization with both partners and non-partners, although findings are stronger for women than men.16, 28, 31, 79–81
In comparison to intimate partner violence, recent NPV (victimization and aggression) among adults has been relatively unaddressed among ED populations outside of those presenting for acute assault-related injury. However, NPV has been studied in other health care settings such as primary care82
and walk-in clinics69
found rates of NPV victimization to be high (45%of young adult males and 48% overall respectively). One prior retrospective ED study of female-to-female violence amongst women83
found that approximately 9% of women presenting to the ED for any reason had been victimized, and of these women, only 5% identified their assailant as being an intimate partner. This study finds also that a surprisingly high number of women seeking ED care have recently been involved in NPV.
Identifying and intervening with patients who have experienced recent NPV and are therefore at increased risk of future violence and injury has significant public health implications. Although there is a paucity of data on effective treatment interventions targeting violence in ED samples, there is evidence to support that addressing substance use is related to reductions in violence, even if the reported substance use and violence were not temporally related initially. For example, studies have found that patients who decrease their substance use (following treatment engagement) experience substantial reductions in violence over time.28, 48, 84, 85
Interventions based on cognitive and behavioral strategies can impact both substance use and violence.86–89
Therefore identifying individuals who report recent substance use and recent violence in the ED may offer an opportunity for intervention.
EDs often serve primary care functions; in this capacity, the ED may be a setting for interventions to interrupt the cycle of violence among patients treated routinely for fistfights, bar fights, and neighborhood disagreements. ED-based substance use interventions may be beneficial in preventing future injury,90
and other more intensive case management interventions have been shown to decrease criminal justice outcomes and violence involvement among admitted trauma inpatients.91
Findings from the regression analysis highlight the impact of substance use beyond that of traditional demographic risk factors (age, gender, employment status). Future studies are needed to evaluate the impact of substance use treatment on patient experiences with violence and associated injury mortality and morbidity.