Drugs and violence - the real issues
Drugs don't make people violent
It is unlikely that drugs, even drugs such as crack cocaine or PCP (Angel Dust), actually make people violent. It is usually the case that those committing violent acts under the influence of drugs have pre-drug use violent histories. Drugs can thus be a catalyst in some cases but not a cause. It is more likely that those with a predisposition towards violence seek out particular drugs that compliment (and that they believe compliment) aggressive behaviour. Expectation of what a drug 'does' to individuals is likely to be equally important and drug use in contexts where different expectations exist result in lesser or greater amounts of aggression/violence.
While various illicit drugs are often associated with violence, it is worth remembering that the consumption of alcohol, (a legal drug), is frequently related to incidents of violent / anti-social behaviour.
Some drugs 'make' you less violent
A number of drugs such as cannabis, ecstasy and heroin appear to have an inverse relationship to violent acts/crime. A number of studies have found that compared to the general, non-drug using population, users of these drugs, (heroin, cannabis, ecstasy) are less likely to be convicted of violence than the non-drug using population. While it is romantic to think of 'love drugs' and drugs that encourage 'peace not war' it is likely that expectation once again has much to do with patterns of associated behaviour.
Some may point to the fact that drugs such as heroin have a sedative effect, but it is also the case that at different points in history heroin has also been associated with violence and been used to 'stimulate' as well as sedate. As with the idea that drugs cause violent behaviour, less (than average) violent behaviour probably has as much to do with users expectations of the drug, the type of individual who chooses to use it (pre-existing violent dispositions), and the context in which use takes place - bars are more likely to produce violent outcomes, although alcohol is served in both, than restaurants.
Drug markets are a locus for violence
The clearest relationship between drugs and violence is that which takes place in the trading of drugs, primarily between those doing the trading. This is a structural relationship based upon the illegality of the drug trade. It has little or nothing to do with the pharmacology of drugs themselves. This violence is motivated primarily by money rather than by any properties of the drugs themselves.
References
Context and expectation:
Gustafson, R. (1990) 'Wine and Male Physical Aggression', The Journal of Drug Issues, Vol 20, No. 1., pp075-086.
Fagan, J. (1993) 'Interactions Among Drugs, Alcohol and Violence', Health Affair, pp.64-79.
Falk, J. L. (1994) 'Drug Dependence: Myth or Motive', in Coomber, R. (ed.), Drugs and Drug Use in Society: A Critical Reader, Dartford, Greenwich University Press.
Fishbein, D. (1996) 'Female PCP-Using Jail Detainees: Proneness to Violence and Gender Differences', Addictive Behaviours, Vol. 21, No. 2, pp155-172.
Haasen, C. and Krasz, M. (2001) 'Myth versus evidence with respect to cocaine and crack: Learning from the US experience', European Addiction Research: 2001, 7 (4), p.159-160.
Kallmen, H. and Gustafson, R. (1998) 'Alcohol and Disinhibition', European Addiction Research, 4: 150-162.
Kinlock, T. (1991) 'Does Phencyclidine (PCP) Use Increase Violent Crime?', The Journal of Drug Issues, Vol 21, No. 4., pp795-816.
Morgan, J. and Zimmer, L. 'The Social Pharmacology of Smokable Cocaine: Not All I'ts Cracked Up to be' in Reinarman, C. & Levine, H. (eds.) Crack in America, London, University of California Press.
Some drugs make you less violent:
Gustafson, R. (1990) 'Wine and Male Physical Aggression', The Journal of Drug Issues, Vol 20, No. 1., pp075-086.
Tonry, M. and Wilson, J. Q. (eds.) (1990) Drugs and Crime, Chicago, University of Chicago Press.
Power, R. (1994) 'Drugs and Crime and Violence', in Coomber, R. (ed.), Drugs and Drug Use in Society: A Critical Reader, Dartford, Greenwich University Press.
Drug Markets are a locus for violence:
Goldstein, P. Brownstein, P. Ryan, P. Bellucci, P. A. (1997) 'Crack and Homicide in New York City: A Case Study in the Epidemiology of Violence', in Reinarman, C. & Levine, H. (eds.) Crack in America: Demon Drugs and Social Justice, London, University of California Press.
