Int. J. Environ. Res. Public Health 2009, 6 1. Introduction 3157 Although historically viewed as a private family matter, for more than 30 years, intimate partner violence (IPV) has been recognized as a broad societal problem that necessitates the attention of both the mental health and criminal justice systems. According to data gathered as part of the National Crime Victimization Survey, in 2005, there were approximately 3.5 million reports of family violence and nearly 1 million female victims of intimate partner violence [1]. Moreover, estimates indicate that approximately 15–20% of partners engage in IPV at least once annually [2]. In addition, the National Center for Victims of Crime reports 32% of college students have experienced violence in a previous relationship and 21% report violence in their current relationship [3]. Acts of IPV range from beating up one’s partner repeatedly to a single episode of pushing one’s partner [2,4-6]. IPV often has serious public health consequences. According to the Department of Justice (DOJ) estimates, over 400 men and 1,200 women are killed by an intimate partner each year [1]. In fact, partner violence accounts for 11% of all homicides annually [6]. In addition, IPV often results in acute injuries (e.g., bruises, lacerations, broken bones and teeth) and may result in chronic illnesses and psychiatric conditions (e.g., chronic pain, substance use; [7,8]). Specifically, a 2001 Department of Justice (DOJ) report indicated there were 691,000 nonfatal violent victimizations committed by current or former spouses, boyfriends, or girlfriends each year. Moreover, nearly a quarter million emergency room visits each year involve a victim of IPV. According to the findings of the National Crime Victimization Survey [1], between 2001 and 2005, nonfatal intimate partner victimizations accounted for 22% of victimizations against women age 12 and older. In addition to the physical consequences, victims of IPV also may experience depression, substance abuse, anxiety, and low self-esteem as a result of the victimization. Related to this, in the United States alone, the economic costs associated with IPV against women is estimated to range from $2.3 billion to $7 billion per year [9]. Results of prior investigations, in a variety of settings, provide evidence of a link between the occurrence of IPV episodes and substance use (i.e., comorbidity model). Although both substance use and partner violence are viewed as observable manifestations of a common set of problems, neither is believed to be a cause of the other [10]. In a national sample of 5,159 families, Kaufman Kantor and Strauss [11] Kaufman Kantor and Strauss found over 20% of males and 10% of females were drinking prior to the most recent and severe act of violence. In the National Crime Victimization Survey [12], 43% of the victims of IPV reported the perpetrator had been under the influence of drugs. Studies of college student populations, which have often focused on forms of IPV that involve sexual violence, have found that 50% of assaults involve alcohol use [13]. Among prisoners convicted of murdering an intimate partner, 45% reported that they were drinking at the time of the incident, with an average blood alcohol concentration of 3 times the legal limit. For married or cohabiting patients entering treatment for alcoholism and other drugs of abuse, the proportion of these dyads reporting at least one episode of IPV in the previous year is 4–6 times higher than observed in national samples [14,15]. In addition, the strong relationship between alcohol use and perpetration of IPV has been found in primary health care settings [16], family practice clinics [17], prenatal clinics [18], and rural health clinics [19]. Yet, as noted by Gil-Gonzalez et al. [20] in their meta-analysis of studies examining the alcohol and partner violence link, these findings must be interpreted with caution since many of these