Behavior disordered is a term frequently used interchangeably with emotionally disturbed or socially maladjusted. These terms describe children who are troubled and who may also cause trouble for parents, teachers, peers, and others. Problems associated with defining and identifying behavior disorders, or conduct disorders, are far more difficult than those relating to physical disabilities. Estimates of the prevalence of behavior disorders vary considerably depending on the criteria used for identification and on whether estimates include mild as well as severe instances. It has been estimated that 15% to 19% of U.S. children and adolescents have problems requiring some form of mental health services. Factors that contribute to the development of behavior disorders vary greatly. They are often classified as genetic or congenital versus social or psychological. Given adequate knowledge of biological history and environment, it is sometimes possible to identify children who may be at greater risk for behavior disorders than others.