While it’s common for adolescents and teens to act on impulse rather than thinking their actions out beforehand, extreme impulsiveness is a risk factor for aggressive or violent behavior, according to the American Academy of Child and Adolescent Psychiatry. Because a teenager’s brain is still developing, the cognitive abilities of judgment, reasoning and emotions are immature and can affect the way a teen behaves.

Drugs and Alcohol

Drugs and alcohol can delay a young teen’s brain development and emotional growth. Teens who abuse alcohol may also have less self-control.

Consequently, drinking too much alcohol can lead to taking part in more risky behaviors. Although more research is needed, the findings of a study conducted by researchers at Rutgers University suggests teens who are moderately impulsive to begin with are more likely to act even more impulsively after drinking heavily. Helene R. White, the study’s lead researcher, explains that heavy drinking reduces impulse control, which may actually lead to more drinking. Results of the study were published in the February 2011 issue of Alcoholism: Experimental and Clinical Research.

Low Serotonin Levels

A scientific review published in the October 2008 issue of the journal Aggression and Violent Behavior reports that low levels of the neurotransmitter serotonin may predispose teens to impulsive aggression that leads to disturbing or violent behaviors. Studies also link imbalances in the serotonin and dopamine systems with poor impulse control and substance abuse. Increasing serotonin and decreasing dopamine activity in the brain can help reduce impulsive aggression characterized by destructive behaviors.