Marijuana and Aggression

Does Smoking Marijuana Cause Aggression?

Marijuana usually has a sedating effect on most users, making it much less likely to cause violence in users than other substances such as alcohol and stimulants (e.g., amphetamines and cocaine).

However, sometimes when marijuana is used it can cause fear, anxiety, panic or paranoia, which can result in an aggressive outburst. For most people, once the effects of the drug wear off, their behavior gradually improves.

Some studies have found support for an association between marijuana use and various types of violence, including relationship or interpersonal violence (Moore TM & Stuart GL, 2005). However, no definitive correlation between marijuana use and violence in adults has been establish; the correlation appears to be stronger in adolescents (Copeland J, Rooke S, Swift W, 2013). Violence in anyone, including marijuana users, often has a multicausal explanation, with numerous factors impacting behavior, such as increased life stress, aggressive personality traits, multidrug use, or a history of violent behavior (Macdonald S, et al., 2008). Marijuana is also part of the global illegal drug market, which may increase the chances of violence occurring in some social interactions.

Additionally, when people are withdrawing from marijuana they can become irritable, which can lead to abusive or aggressive behavior among people with a history of aggression (Smith PH et al., 2013).  Studies have not found an association between withdrawal symptoms and aggression among those without a previous history of aggression.

Why Do People Become Abusive or Aggressive?

Using marijuana can produce strange behavior and reactions in people when they are intoxicated. These reactions can be similar to psychosis and paranoia and because of this, marijuana users may experience confusion or a sense of feeling threatened or frightened.

When people stop using marijuana they may experience a variety of withdrawal symptoms including:

Experiencing any of these symptoms can make a person angry, which is an emotional response to feeling threatened or frustrated. Anger ranges from mild irritation to violent rage. Some people can express their anger in a controlled and constructive way while others lash out in an aggressive, uncontrolled way, either immediately or letting their feelings build up. This can lead to intimidating, violent or bullying behavior, endangering them, other people and property.

How Can You Respond to Threatening or Violent Behavior?

The impact and the effects of violence on an individual can be profound and long-lasting, so doing all you can to prevent violence actually occurring is important.

The aim of calming someone down is not to prove them right or wrong, but to allow them to regain control of their behavior without resorting to violence.

The best time to intervene is when a person is feeling anxious. Be supportive, empathic and neutral. Ask them what is wrong and try to calm them down. Move them to a quiet place and stay with them until the effects of marijuana wears off.

If a person's behavior becomes aggressive, you could try the following tips to help calm them down:

After the effects of marijuana or marijuana withdrawal wear off, talk to your friend about what happened, how it affected you and those around you, and how this can be prevented in future.  See also the Looking After a Friend factsheet.

How to Help Prevent Aggressive and Violent Behavior From Happening Again

As a friend, you can do things that may reduce the likelihood of this happening to them again. These may include the following:


This information adapted with permission from the National Cannabis Prevention and Information Centre in Australia.