Child disruptive behaviour disorders (DBDs), namely, conduct disorder (CD), and oppositional defiant disorder (ODD) as described by DSM-IV, are among the most common reasons for referring children and adolescents to mental health services. Often, DBDs co-occur with attention deficit hyperactivity disorder (ADHD). Children with persistent high levels of aggressive, oppositional, and impulsive behaviours early in life are at a higher risk of serious adolescent and adult antisocial behaviour and criminal activity. Although the prevalence rates of DBDs in the Dutch population has only been studied to a certain degree, one study concerning the prevalence of child psychiatric diagnoses of children between the ages of 6 and 8, using a structured diagnostic interview, revealed a mean prevalence rate of 12.8% for DBDs; 9.3% for girls and 15.2% for boys.