Do Drugs Make People Violent? Exploring the Connection Between Cannabis and Aggression

What comes to mind when you think about drugs? One might recall wild parties and drunken adventures or violent crime, delinquency, and poverty. Our perception of drugs is heavily influenced by their portrayal in the media. Popular media has been used to portray drug users and traffickers as dangerous and out of control (Boyd, 2002). This type of media legitimized the war on drugs and the need for the government to protect citizens from violent crime. How much of our ideas about drugs and those who use them are shaped by anti-drug propaganda? In the 1930s mainstream media depicting cannabis was intended to discourage young people from smoking weed. One popular movie from 1936 Reefer Madness showed college students who under the influence of marijuana committed murder, rape, suicide, and succumbed to psychosis. Despite no evidence of that cannabis caused such extreme behavior, these deceptions led to the idea that weed was dangerous which resulted in the Marijuana Tax Act in 1937 effectively banning the drug (Smith, 1986).

Today people tend to stereotype stoners as lazy bums however the association of weed with crime is still prevalent especially when it involves the arrests of people of color. The police often use drugs to justify excessive violence against people of color. The way we talk about and portray drugs determines how people who use drugs are treated. One study found that although White people were more likely to exhibit criminal behavior, Black people were more likely to be arrested for the use of marijuana and hard drugs (Koch & Lee, 2016). Anti-drug propaganda and associations with people of color can cloud judgement and be used to support racist and unjust practices.  

Is there any scientific backing for the association between drug use and aggression? Hoaken and Stewart (2003) identified three ways that drugs influence behavior. First is the intoxicating effects. This includes altering of the psychomotor system, dampening of internal inhibiting mechanisms, reduction of pain sensitivity and some cognitive capacities. In combination these effects may make a person who is intoxicated more likely to have risky decisions, react to threats and to act defensively. 

The second way drugs influence behavior is through their neurotoxic effects which refers to the changes in the brain that occur due to prolonged drug use. Finally, withdrawal from drugs can influence behavior. People may become violent to obtain drugs, particularly to avoid the painful symptoms of withdrawal. Other risk factors that may lead people to act aggressively when using drugs are genetics and history of mental illness.  

Certainly, drug use can lead to aggressive and violent behavior, but this is not always the case. Several studies looking at the effect of cannabis on aggression found that high doses of THC, (the psychoactive component in weed) actually suppressed aggression. Taylor et al., 1976 looked at aggression with high and low does of THC and alcohol in male college students. The participants were told that they could administer a shocks of varying intensity to their opponent and that whoever was faster would avoid the shock. Higher levels of THC reduced the intensity of the shock given while higher levels of alcohol increased mean shock setting. Perna et al., 2016 found similar results using an aggression paradigm where heavy alcohol and regular cannabis users could presses buttons to either add money to their own tally or subtract points from their opponent’s tally.

In California, where cannabis is legal, no relationship was found between law permitting dispensaries and reports of violent crime (Hunt et al., 2018). What is of most concern is the stigma that affects people who use drugs. Unfortunately, people who use drugs are often stripped of their humanity, viewed as immoral or helpless people who are complicit in their own struggles. Our perception of how dangerous drugs are is impacted by the media’s portrayal of drugs and drug users. It is important to remember that while drugs can increase aggression, drug use is not synonymous with violence. The stigma attached to drug use can be just as detrimental to a person’s life as the effects of drugs themselves.


Boyd, S. (2002). Media constructions of illegal drugs, users, and sellers: a closer look at Traffic. International Journal of Drug Policy13(5), 397-407.

De Sousa Fernandes Perna, E. B., Theunissen, E. L., Kuypers, K. P. C., Toennes, S. W., & Ramaekers, J. G. (2016). Subjective aggression during alcohol and cannabis intoxication before and after aggression exposure. Psychopharmacology233, 3331-3340.

Hoaken, P. N., & Stewart, S. H. (2003). Drugs of abuse and the elicitation of human aggressive behavior. Addictive behaviors, 28(9), 1533-1554.

Hunt, P., Pacula, R. L., & Weinberger, G. (2018). High on crime? Exploring the effects of marijuana dispensary laws on crime in California counties.

Koch, D. W., Lee, J., & Lee, K. (2016). Coloring the war on drugs: Arrest disparities in black, brown, and white. Race and Social Problems8, 313-325.

Smith, R. (1968). US marijuana legislation and the creation of a social problem. Journal of Psychedelic Drugs2(1), 93-104.

Taylor, S.P., Vardaris, R.M., Rawtich, A.B., Gammon, C.B., Cranston, J.W. and Lubetkin, A.I. (1976), The effects of alcohol and delta-9-tetrahydrocannabinol on human physical aggression. Aggr. Behav., 2(1):153-161.<153::AID-AB2480020206>3.0.CO;2-9

One thought on “Do Drugs Make People Violent? Exploring the Connection Between Cannabis and Aggression

  1. In the Taylor (1976) and Perna (2016), did they see if there are differences in reaction time when it came to the participants intoxicated with alcohol vs. cannabis? If there is a difference, I wonder if this confounds the perceived reduction in aggression.


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