摘要：Objectives. We examined whether frequent drug use increases the likelihood of subsequent sexual or physical intimate partner violence (IPV) and whether IPV increases the likelihood of subsequent frequent drug use. Methods . A random sample of 416 women on methadone was assessed at baseline (wave 1) and at 6 months (wave 2), and 12 months (wave 3) following the initial assessment. Propensity score matching and multiple logistic regression were employed. Results . Women who reported frequent crack use at wave 2 were more likely than non–drug using women to report IPV at wave 3 (odds ratio [OR]=4.4; 95% confidence interval [CI]=2.1, 9.1; P <.01), and frequent marijuana users at wave 2 were more likely than non–drug users to report IPV at wave 3 (OR=4.5; 95% CI=2.4, 8.4; P <.01). In addition, women who reported IPV at wave 2 were more likely than women who did not report IPV to indicate frequent heroin use at wave 3 (OR=2.7; 95% CI=1.1, 6.5; P =.04). Conclusions . Our findings suggest that the relationship between frequent drug use and IPV is bidirectional and varies by type of drug. Over the past decade, intimate partner violence (IPV) has emerged as a significant public health problem among women in drug treatment. Past-year prevalence rates of experiencing IPV have been found to range between 25% and 57% among women in drug treatment, 1– 3 compared with rates of 1.5%–16% found in epidemiological surveys of community-based samples of women. 4– 6 Research on the relationship between substance abuse and IPV has focused primarily on how a perpetrator’s substance abuse increases the risk of IPV. 7– 9 Accumulating research has also found significant associations between women’s drug use and their victimization from IPV. 1, 2, 10, 11 Recent, frequent use of illicit tranquilizers, marijuana, cocaine, crack, and heroin has been found to be associated with experienced IPV in cross-sectional studies of women in methadone maintenance treatment programs (MMTPs). 1, 2, 11 Research has yet to elucidate fully the causal relationships between women’s drug use and experiencing IPV: Does women’s drug use contribute to IPV? Does experiencing IPV lead to an increase in drug use? Or is there a reciprocal relationship between IPV and drug use? The first possibility considered, that drug use leads to IPV, can be explained by several overlapping psychopharmacological, economic, and gender-related power factors. Psychopharmacological explanations focus on how drug use induces cognitive disruption and impairs the ability to process social interactions for the perpetrator and victim of IPV. 12 These cognitive disruptions may lead to paranoia, impair judgment, and distort cues, increasing the likelihood of a violent interaction. 13 IPV occurs as an extension of the unequal distribution of power, social status, labor, and drugs between intimate partners. 14– 17 Qualitative research suggests that conflicts over spending money on and sharing drugs often lead to arguments that escalate to IPV. 18– 20 Because drug-dependent women are often deemed “sexually promiscuous” and are perceived as violating traditional gender norms, their partners may feel more justified in perpetrating violence against them. 16, 21, 22 The second possibility considered, that IPV leads to the use of illicit drugs, is supported by qualitative studies documenting that women initiate or increase their illicit drug use to cope with the pain of experiencing IPV. 23, 24 The use of tranquilizers or marijuana was cited as a frequent self-medication response to the physical and emotional pain experienced immediately after an episode of IPV in a study of abused women in MMTPs. 25 The third alternative causal explanation posits a reciprocal relationship between IPV and drug abuse: drug abuse increases IPV, and IPV also increases the likelihood of drug abuse. 24, 26 A longitudinal investigation by Kilpatrick et al. 24 using a national probability sample of 3003 women found that a woman’s drug use at a single point in time increased her odds of experiencing a violent assault in the subsequent 2 years by a factor of 1.84 after control for background factors. This study also estimated that new assaults increased the odds of drug use by a factor of 2.3 in the subsequent 2 years, after control for background variables. Kilpatrick et al.’s study was limited by its focus on physical assaults in general, as opposed to IPV, and its failure to control for potentially confounding psychosocial variables. A fourth plausible explanation is that instead of a direct association, several psychosocial variables are independently associated with both IPV and drug abuse. A wide range of psychosocial mediators have been found to be associated with both IPV and drug use, 27– 30 including posttraumatic stress disorder (PTSD), 31, 32 lack of social support, 11 childhood sexual abuse, 33– 37 and HIV risk behavior. 25 These potential confounders need to be considered when examining the relationship between drug use and IPV. In our study, data were collected in 3 waves (i.e., at baseline and 6 and 12 months later) to examine the temporal relationship between frequent drug use and IPV among a random sample of 416 women in MMTPs. We tested 3 hypotheses. Hypothesis 1 was that frequent drug use increases the likelihood of subsequent IPV. We tested whether women in MMTPs who reported frequent use of cocaine, crack, heroin, marijuana, or frequent binge drinking at wave 2 were at higher risk of physical or sexual IPV at wave 3 than were women in MMTPs who did not use these drugs at wave 2, after control for background and relationship factors at wave 1. Hypothesis 2 was that IPV increases the likelihood of subsequent frequent drug use. We tested whether women who reported IPV at wave 2 had greater odds than women who did not report IPV at wave 2 of reporting frequent use of crack/cocaine, heroin, marijuana, or frequent binge drinking at wave 3, after control for background and relationship factors at wave 1. Hypothesis 3 was that the relationship between frequent drug use and IPV is reciprocal. This hypothesis was tested indirectly: if hypothesis 1 and hypothesis 2 were supported for a particular drug, then we can conclude that hypothesis 3 is supported for that drug.
