According to criminology professor Larry Siegal from the University of Massachusetts, "If you chose ten kids at random, it would not be difficult to pick the ones who are at risk of becoming criminals. It is not magic. There are certain symptoms like short attention span, lack of impulse control, and poor home life that are likely predictors of criminal behavior." What other factors may lead a person to break the law?

Some researchers believe that the hormone testosterone plays a role in criminal behavior. This hormone, which is responsible for male physical characteristics and behavior traits, such as aggression and impulsivity, floods the bodies of adolescent boys. As a result, some boys go through an adolescent delinquent period, although most do not go on to pursue a life of crime. "A teenage boy will commit a crime at 15 that he would not dream of doing at 25. If we can keep him out of prison, he may grow out of it," reports Jack Levin, professor of sociology and criminology at Northeastern University in Massachusetts. Those who do become criminals are influenced by other factors, such as psychological qualities.

One common type of career criminal is the person with antisocial personality disorder (also called sociopathy or psychopathy). This disorder is characterized by a lack of conscience, inability to empathize with victims, manipulative behavior, and pathological lying. In the United States, approximately 3.6% of the population has antisocial personality disorder. And, among prisoners, it has been estimated that 47% of men and 21% of women have the disorder.

What causes a person to become antisocial? It seems that both genetics and the environment (nature versus nurture) play a role in antisocial personality disorder. Researchers have discovered that certain factors in the home may increase a child's risk, such as being abused or neglected. While there are therapy programs and medicines available to help with other conditions (like depression), antisocial personality disorder is very challenging to treat, especially considering that the person may also have an alcohol or drug abuse problem.

According to the Federal Bureau of Investigation's Uniform Crime Report, these factors can increase a person's risk of breaking the law:

• Being between the ages of 15-24 years—This population commits more crimes.
• Not having a stable homelife (e.g., moving a lot) and having a lot of conflict in the home
• Having a low socioeconomic status

Researchers are also particularly interested in why people commit violent crime. Studies have shown that juveniles and adults who were abused as children are more likely to be arrested for committing a violent act. Some, but not all, evidence supports the idea that having a history of head trauma is associated with violence. What does seem clear is that the factors that lead a person to violence are very complex, involving genetics, the environment, and issues relating to physical and mental health. Early intervention may be the key to lowering a child's risk of committing a crime as a teen or as an adult.