Physical violence among a prospective cohort of injection drug users: A gender-focused approach

Abstract

Although dramatically heightened rates of violence have been observed among injection drug users (IDU), little is known about the gender differences associated with violence among this population. Employing a risk environment framework, we performed an analysis of the factors associated with experiencing violence among participants enrolled in a prospective cohort study of IDU during the years 1996–2005 using generalized estimating equations (GEE). Among 1114 individuals, 291 (66%) of females and 470 (70%) of males reported experiencing violence during the study period. In multivariate analyses, mental illness, frequent alcohol use, frequent crack use, homelessness, Downtown Eastside residency, and requiring help injecting were positively associated with experiencing violence for both sexes (all p < 0.05). For females, binge drug use (AOR = 1.30) and drug dealing (AOR = 1.42) were positively associated with violence, while younger age (AOR = 1.02), frequent heroin injection (AOR = 1.24), and incarceration (AOR = 1.50) were significant for males. Women were more likely to be attacked by acquaintances, partners, and sex trade clients, while men were more likely to experience violence from strangers and the police. These findings indicate that susceptibility to violence among IDU is structured by environmental factors such as homelessness and drug-related factors such as frequent alcohol use and involvement in drug economies. Furthermore, important gender differences with respect to the predictors and characteristics of violent attacks do exist. These findings indicate an urgent need for the development of comprehensive programs and structural interventions that take a gender-focused approach to violence among IDU.

Introduction

Violence is a major cause of morbidity and mortality among injection drug users (IDU) that often manifests at the everyday, structural and symbolic levels (Bourgois et al., 2004, Kohli et al., 2005). Many studies have documented drastically elevated rates of physical violence among IDU recruited from both drug treatment programs and street-based settings (Chermack and Blow, 2002, Farris and Fenaughty, 2002, Vlahov et al., 1998). For example, a study of partner violence among women in methadone treatment found that over three-fourths reported ever experiencing violence, while over one quarter reported physical violence in the past year (El-Bassel et al., 2000). Beyond the direct physical injury that results from violence is a range of other health-related harms. Impairments in mental and emotional health resulting from violent encounters include depression, anxiety, suicidal ideation, posttraumatic stress disorder, mood and eating disorders, and substance dependence (Farley and Barkan, 1998, Fischbach and Herbert, 1997, Taylor and Jason, 2002).

The experience of violence among IDU has also been associated with an array of HIV-related risk behaviours (Braitstein et al., 2003, El-Bassel et al., 2000, Gilbert et al., 1997, Vlahov et al., 1998). The majority of these studies have focused on the past traumatic experiences and current social- and individual-level factors that result in a concomitant relationship between violence and HIV risk among marginalized, injection drug using women. For example, one study examining violence and HIV risk behaviours among female partners of male IDU observed that almost half had been physically assaulted by their sex partners; furthermore, those who had experienced physical violence were more likely to engage in unprotected anal intercourse (He et al., 1998). A study of IDU living in Vancouver found historical sexual abuse to be associated with sex trade work, sharing syringes with HIV-positive people, and other health-related harms such as accidental overdose (Braitstein et al., 2003). Intimate partner violence among women in methadone treatment has been associated with visiting shooting galleries, living with someone with drug or alcohol abuse problems, and exchanging sex for money or drugs (El-Bassel et al., 2000). Other risk factors and correlates of physical violence that have been documented among populations of drug-using women include: younger age (Vlahov et al., 1998); being separated or divorced (Gruskin et al., 2002); inconsistent condom use (El-Bassel et al., 2005); having multiple sex partners (Wenzel et al., 2004a); unstable housing (Wenzel et al., 2004b); marijuana use (Burke et al., 2005); and frequent alcohol use (Chermack and Blow, 2002). Childhood sexual and physical abuse is also commonly found to be a strong and independent predictor of adult physical violence among women currently using illicit drugs and among those enrolled in drug treatment programs (Gilbert et al., 1997).

Although few studies have examined the risk factors for received violence among male substance users, the prevalence of physical violence among this population is also strikingly high (Finlinson et al., 2003). One study examining received violence in a sample of individuals participating in substance abuse treatment found no gender difference in the proportion of participants reporting violence from partners (61% vs. 65% among men and women, respectively), while males reported higher rates of violence from non-partners (75% vs. 45% among men and women, respectively) (Chermack et al., 2001). Although the expression of violence has traditionally been associated with masculine gender roles, which in turn are at least partially responsible for the linking of partner violence perpetuation and sexual risk behaviours (Santana et al., 2006), received violence among male IDU is also common and likely underreported. As noted by Chermack et al. (2001), studies that do not include both male and female participants and do not examine violence outside of the partner or marital context result in a limited understanding of the gender-related issues that influence physical violence. Furthermore, studies that examine primarily individual-level factors (e.g., age, ethnicity, education) cannot account for the gendered structures and social relations within the drug economy and street environment that perpetuate everyday violence experienced by IDU (Epele, 2002).

Over the past several decades, numerous theoretical models have been developed to guide our understanding of the complex relationship between drugs, alcohol and violence (Parker and Auerhahn, 1998). One of the most commonly used frameworks is that first proposed by Goldstein, in which three categories are used to describe the factors that link drugs and violence (Fagan, 1993, Goldstein, 1985, Goldstein et al., 1989): (1) pharmacological (i.e., pharmacological effect of substances enhance violent behaviour and individuals under the influence of drugs are less aware of surroundings making them vulnerable to violence); (2) economical compulsive (i.e., engagement in economically oriented violent crime to sustain drug use behaviours); and (3) systemic (i.e., the endemicity of violent interactions within the system of drug distribution and use). Although this framework is often used as a theoretical explanation for the observed link between violence, crime and substance use, several authors have noted that only limited empirical evidence exists to support all three components of the conceptual model (Martin and Bryant, 2001, Parker and Auerhahn, 1998). For example, in a review of illicit drug use and violence, Martin and Bryant (2001) found only limited evidence of a pharmacological basis for an association between illicit drug use and violence, and go on to suggest that most researchers emphasize a social rather than psychopharmacological basis for the link between cocaine use and violence. We hypothesize that “risk environment” theory may provide a more appropriate theoretical approach to understanding the multilevel factors which influence exposure to physical violence among IDU. Risk environment theory posits that the physical, social, economic, and policy environments in which drug use takes place structures and shapes the production and re-production of HIV risk (Rhodes, 2002). Given that this theory has been used effectively to conceptualize the multifactorial influences that produce HIV risk among IDU (Rhodes et al., 2005), a similar approach may be useful for describing the “risk environment” factors that structure susceptibility to physical violence among this population.

Although it has been shown in various settings that epidemics of HIV and violence are closely linked (Maman et al., 2000, Quinn and Overbaugh, 2005), little is known about the experiences of physical violence among IDU in the Downtown Eastside area of Vancouver, the city's drug scene epicenter. Given that an HIV epidemic among IDU in this area has persisted since the mid 1990s, with HIV prevalence rates estimated to be greater than 30% (Kuyper et al., 2004), characterizing physical violence and its potential association with HIV risk production may be useful for informing programs, policies and interventions targeting this population. Furthermore, there is a lack of information regarding the gender differences associated with experiencing physical violence among individuals who inject drugs. In response to these concerns, the present study was conducted to examine physical violence, both partner violence and other types of assault, among a prospective community-recruited cohort of male and female IDU. Thus, the objectives of this study were to: (1) determine the prevalence of experiencing physical violence among this cohort of IDU; (2) examine the gender differences associated with risk factors for physical violence; and (3) compare the characteristics of experiencing violence, including the perpetrator and type of attack (beating, attack with a weapon, etc.) experienced by men and women in this setting.