(BJS, 1993). However, the majority of crimes committed by drug users are of a nonviolent nature (e.g., shoplifting, prostitution) (Goldstein, 1985).
One of the most complex and controversial links between drug abuse and violence has been the potential relationship between the pharmacological effects of alcohol or illicit drugs and violence. Individuals initially use alcohol or illicit drugs because they produce some noticeable change in mood or emotional state; the extent and nature of that change varies depending on the specific drug or drug combination and the individual. However, it is difficult to determine a simple cause-effect relationship between the pharmacological actions of alcohol or illicit drugs and an individual's violent behavior because of the many interacting physiological, psychological, and social variables, each of which can have an impact on the drug-violence connection (NRC, 1993). At the biological level, differences between individuals include the amount and chronicity of drug use as well as individual variations in endocrine mechanisms (e.g., modulation of aggression by androgens), neurotransmitter activity, and genetic interactions (Miczek et al., 1994a). At the psychosocial level, risk factors correlated with an increase in aggressive or violent behavior associated with alcohol and illicit drug use include gender (which may involve biological, expectational, and social factors) childhood aggression (associated with alcohol and violent behavior) and co-occurring psychiatric disorders (discussed in more detail below) (NRC, 1993). Macrosocial factors also play a determining role in the link between violence and drug abuse. There are striking cultural and subcultural differences associated particularly with alcohol use and violence (Miczek et al., 1994b). The drug user's expectations and the situation or environment in which drug use takes place are additional macrosocial factors. Research on the link between drug abuse and violence is also complicated by the difficulties inherent in replicating realistic conditions or precursors of violence in laboratory studies on animals or humans (see Chapter 2).
The following sections present an overview of current knowledge on the pharmacological links between drug abuse and violence, followed by a discussion on directions for future research. This overview draws heavily from recent comprehensive reviews of the literature (NRC, 1993; Miczek et al., 1994b).
Alcohol is the drug most studied and most closely associated with violence, although a simple cause-effect relationship has not been estab-