ADHD and conduct disorder (CD) are highly comorbid, with rates of CD in individuals with ADHD ranged from 3.1% to 41.0% while the rates of ADHD in those with CD ranged from 13.9% to 100%.
Both disorders are longitudinally associated with outcomes that have serious implications for an individual's functioning and wellbeing. For ADHD, the findings indicated the disorder was significantly associated with adverse outcomes across academic, employment, and service use domains and several outcomes relating to mental and substance use disorders and criminality. Similarly, CD was found to be associated with a range of substance use disorders, violence, early pregnancy, antisocial personality disorder, and failure to complete high school.
Many of the adverse outcomes associated with ADHD and CD, particularly other mental and substance use disorders, may persist over the lifespan.
The symptoms of the disorder may be directly associated with the outcome. For example, impulsivity associated with ADHD may increase the proclivity towards substance use disorders. Second, these findings may indicate a shared genetic liability as theorised to exist between ADHD and bipolar disorder. Third, the adverse psychosocial outcomes associated with ADHD and CD may lead to other mental disorders. For example, failure to complete high school (which was found to be associated with both ADHD and CD) can result in unemployment and financial stress, increasing the likelihood of common mental disorders such as anxiety, depression, or substance use disorder.
As such, ADHD and CD are associated with a complex interplay of adverse outcomes that affect not only the individual, but families, communities, and offspring.
The prevention and effective treatment of ADHD and CD have the potential to not only reduce adverse health outcomes but also avert a wide range of adverse psychosocial consequences. Erskine, H. E., Norman, R. E., Ferrari, A. J., Chan, G. C. K., Copeland, W. E., Whiteford, H. A., & Scott, J. G. (2016). Long-Term Outcomes of Attention-Deficit/Hyperactivity Disorder and Conduct Disorder: A Systematic Review and Meta-Analysis. Journal of the American Academy of Child & Adolescent Psychiatry, 55(10), 841–850. doi:10.1016/j.jaac.2016.06.016