The study found that children who were slightly impulsive and had mild behavioral problems in pre-school often faced harsh disciplinary action from parents and teachers. Instead of having the desired effect, these actions further alienated the children, often making the child more aggressive and preventing him or her from learning important social and cognitive skills.
As a result, these young children were unprepared for school and often developed social problems; punishments like being sent to the principal’s office meant losing more class time and falling further behind.
By the time the children were in their teens, their parents spent less and less time with them, possibly in order to avoid conflict. With the parents providing less supervision, the children gravitated to similarly estranged peers, Dr. Dodge said.
via A Cascade of Influences Shaping Violent Teens – NYTimes.com