Violence Prevention

Violence Associated with Substance Abuse

Numerous types of violence are associated with some forms of substance abuse. Although admittedly an oversimplification, for the purposes of this discussion, these types can be dichotomized into violence that is related to the pharmacological effects of the substance and violence that does not meet this criterion. The first category refers to violence occurring after ingesting alcohol or drugs or during withdrawal, or violence resulting from long-term use. Examples include violence as a result of intoxication or agitation resulting from withdrawal symptoms. The second category refers to instrumental aggression that occurs due to the expense associated with purchasing substances or the result of the illegal status of the substance. Examples include assault and robbery to support one's addiction, gang warfare over territory, and retribution (e.g., for a drug deal gone bad). Because the prevention of such types of violence typically requires resources that are unavailable to most mental health professionals, this entry primarily focuses on violence associated with the pharmacological effects of alcohol and drugs.

Substances Associated with Aggression

Because most of the research on aggression and substance use is correlational, one must be careful about assuming causal relationships. Controlled experimental studies are helpful for inferring causal associations between manipulated situational variables, measured personality variables, and pharmacological effects on [Page 994]aggressive behavior. However, with the exception of alcohol, experimental studies are either uncommon or nonexistent in this literature. In the United States, two of the most frequently used substances are alcohol and marijuana. The empirical evidence for the pharmacological effects of alcohol in increasing aggression is overwhelming. In contrast, the evidence for marijuana suggests no causal relationship between its pharmacological effects and violence.

Among all the substances of abuse, alcohol has the most consistent relation with violence in the research literature. Alcohol is the most common substance found among victims of violence and perpetrators, although this result is confounded with its widespread availability and abuse. A 1998 U.S. Department of Justice report found that approximately 3 million alcohol-related violent crimes occur each year and that about two thirds of these crimes were characterized as assault. Acute alcohol use by the perpetrator is especially likely in intimate partner violence (about two thirds of cases) relative to violence by strangers (about one third of cases). Alcohol is also involved in a large number of homicides and suicides. Estimates of alcohol use by offenders prior to committing homicide are typically quite high (up to 86%). A 2005 Australian government report found that 47% of homicide perpetrators had consumed alcohol at the time of the murder and 32% had consumed illegal drugs. Perhaps the strongest evidence for a causal role of alcohol is found in several meta-analyses of laboratory experiments. These data have revealed consistent relationships between alcohol and aggression, most often in the presence of provocation (see below).

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