a1 Department of Health Care Policy, Harvard Medical School, Boston, MA, USA
a2 Departments of Psychiatry and Child and Adolescent Psychiatry, NYU School of Medicine and Psychiatry, NY VA Harbor Healthcare Service, New York, NY, USA
a3 University of Michigan, Institute for Social Research, Ann Arbor, MI, USA
a4 School of Education, Boston University, Boston, MA, USA
a5 Division of General Pediatrics, Children's Hospital Boston, Harvard Medical School, Boston, MA, USA
a6 Institute for Development Research, Advocacy, and Applied Care (IDRAAC), St George Hospital University Medical Center, Beirut, Lebanon
a7 Shire Development Inc., Wayne, PA, USA
Background Although DSM-IV attention deficit hyperactivity disorder (ADHD) is known to be associated with numerous adverse outcomes, uncertainties exist about how much these associations are mediated temporally by secondary co-morbid disorders.
Method The US National Comorbidity Survey Replication Adolescent Supplement (NCS-A), a national survey of adolescents aged 13–17 years (n = 6483 adolescent–parent pairs), assessed DSM-IV disorders with the World Health Organization (WHO) Composite International Diagnostic Interview (CIDI). Statistical decomposition was used to compare direct effects of ADHD with indirect effects of ADHD through temporally secondary mental disorders (anxiety, mood, disruptive behavior, substance disorders) in predicting poor educational performance (suspension, repeating a grade, below-average grades), suicidality (ideation, plans, attempts) and parent perceptions of adolescent functioning (physical and mental health, interference with role functioning and distress due to emotional problems).
Results ADHD had significant gross associations with all outcomes. Direct effects of ADHD explained most (51.9–67.6%) of these associations with repeating a grade in school, perceived physical and mental health (only girls), interference with role functioning and distress, and significant components (34.5–44.6%) of the associations with school suspension and perceived mental health (only boys). Indirect effects of ADHD on educational outcomes were predominantly through disruptive behavior disorders (26.9–52.5%) whereas indirect effects on suicidality were predominantly through mood disorders (42.8–59.1%). Indirect effects on most other outcomes were through both mood (19.8–31.2%) and disruptive behavior (20.1–24.5%) disorders, with anxiety and substance disorders less consistently important. Most associations were comparable for girls and boys.
Conclusions Interventions aimed at reducing the adverse effects of ADHD might profitably target prevention or treatment of temporally secondary co-morbid disorders.
(Received November 20 2012)
(Revised August 16 2013)
(Accepted August 25 2013)
(Online publication October 08 2013)