A somewhat loose term with three major applications. First, it is occasionally applied to any type of abnormal behavior, or behavior pathology, and in this sense is roughly equivalent to “psychiatric disorder” or “mental disorder.” Second, it is used as a synonym for “conduct disorder,” referring to a pattern of impulsive antisocial behavior not accompanied by neurotic anxiety or psychotic misinterpretation of reality. In this sense the term is applied to many types of unacceptable behavior (stealing, assault, forgery, pathological lying, rape) when this behavior stems from a persistent personality disturbance whose major characteristic is failure to conform to social and ethical standards. In its third application, the term behavior disorder, or “primary behavior disorder,” partially overlaps with the second usage, but is applied specifically to a variety of psychiatric disorders of children and adolescents resulting from an unfavorable environment rather than from organic disease or defect. These disorders include the following major types: (a) undesirable traits and habit disturbances such as temper tantrums, nail biting, persistent thumb sucking, enuresis, and excessive masturbation; (b) conduct disorders such as cruelty, fire setting, continual lying, vandalism, sex offenses, glue sniffing, use of alcohol or drugs, stealing and other delinquencies; (c) certain neurotic symptoms such as tics, stuttering, somnambulism, and overactivity; (d) school difficulties such as disruptive behavior, school phobia, and truancy.