Disruptive behaviour disorders
ADHD is highly comorbid with disruptive behaviour disorders
including oppositional defiant disorder (ODD) and conduct
disorder (CD); as many as 50% of children also display CD or
ODD (Biederman et al. 1991; Faraone et al. 2002). Early intervention
may be key with children displaying early signs of
hyperactivity and disruptive behaviour, given the added
complexity and more adverse long-term outcomes associated
with comorbid behavioural problems (Connor et al. 2010).
In addition, evidence suggests that children with ADHD and
established behaviour problems tend to be more resistant to
treatment (Villodas et al. 2012).