Violence connected to drug and alcohol use has had a significant impact on society. Substance abuse can cause people to act violently as a direct result of drugs' effects on the brain. Drugs can also lead to violence in indirect ways. For example, drug users are more likely to commit crimes, some of which may be violent, in order to obtain drugs or the money to buy drugs. Evidence suggests that the sale and distribution of illegal drugs causes violence in both sellers and buyers.

Researching Drugs and Behavior

The link between drugs and aggression and violent behavior depends on the type of drug and the person who uses the drug. Some drugs directly activate brain mechanisms that control aggression, mostly in individuals who have already shown aggression in the past. Research using animals has allowed scientists to...