Along with oppositional defiant disorder (ODD), conduct disorder is considered a disruptive behavior disorder and it is one of the most common mental health disorders diagnosed in young people.
Young people with this condition can be cruel and violent towards others, including pets and other animals. They may be destructive, breaking and damaging property.
The behavior associated with conduct disorder is not limited to occasional outbursts. It is consistent and repetitive, occurring frequently enough that it interferes with the child’s education, family life, and social life.
Source: Conduct disorder: Symptoms, treatment, and causes : Medical News Today