DBD or Disruptive Behavior Disorder is a collective disorder that includes one or more of three primary disorders - ADHD, ODD, and CD.
Children who have chronic difficulties in maintaining attentional focus, completing work, being impulsive, or repeatedly engage in antisocial behaviors such as lying and cheating may have one or more Attention-Deficit and Disruptive Behavior Disorders. The disorders in this category include Conduct Disorder, Attention-Deficit Hyperactivity Disorder, and Oppositional Defiant Disorder. These three disorders are grouped together within the same category because of similarities between symptoms and prevalence rates For example, children with these disorders often have academic difficulties, poor social skills, and impulsivity (i.e., a tendency to act without thinking through potential consequences). In addition, boys far exceed girls in terms of rates of occurrence (although some researchers suggest that girls with ADHD may be overlooked because they tend to be more inattentive than hyperactive).
Disruptive behavior disorders are the most frequent reasons children are referred for mental health practitioners for probable treatment.
However many children with oppositional defiant disorder or conduct disorder are found to have neurologically related symptoms over time, the primary problem is behavior.
Studies indicate both biological and environmental causes for disruptive behavior disorders. Young people most at risk for oppositional defiant and conduct disorders are those who have low birth weight, neurological damage or Attention Deficit.
Source - Terri Rathburn:Your Web Therapist
There are three main types of childhood disruptive behavior disorder. Attention deficit hyperactivity disorder (ADHD) is a disorder characterized by inattentive, hyperactive, and impulsive behaviors. Oppositional defiant disorder is a childhood disorder where a child is excessively disobedient and hostile. Conduct disorder is a more severe form of oppositional defiant disorder where disobedient behavior leads to bullying and even criminal acts.
There is no single known cause of disruptive behavior disorder. Genetics do play a role in ADHD, and fetal exposure to alcohol is a contributing factor.
Source - wiseGEEK