Distinction between Episodic Mood Disorder and Attention Deficit Disorder with Hyperactivity based on their Association with the Main Classes of International Classification of Disease in a Child and Adolescent Population

Background: Few studies comprehensively examine specific mental disorders in terms of associated bio-medical comorbidities with focus on the pattern of similitude and distinction. The present study compares the profile of independent classes of physical disorder for Episodic Mood Disorder (EMD), Attention-Deficit Disorder with Hyperactivity (ADHD) and all Other Mental Disorders (OMD). Methods: Physician billing data for 235893 individuals up to 18 years old spanning sixteen fiscal years (1994-2009) in Calgary, Alberta, was compiled, permitting the examination of Odds Ratios (ORs) comparing the main classes International Classification of Diseases (ICD) within each of four groups of psychiatric disorders: EMD, ADHD, both EMD/ADHD and OMD. Results: Each group profile was distinct: The EMD group presented Odds Ratios (OR) greater than ADHD and all other mental disorder across most ICD classes. For both sexes, ADHD and EMD differed significantly in profile across 11 independent ICD disorder classes, with an additional three classes being specific to females and one specific to males. The ADHD group ORs tended to be lower than the EMD group and the OMD group. Conclusion: This study represents the premiere pediatric populationbased report on the patterns of main class ICD disorders associated with EMD and ADHD and OMD. In opposition with most research focusing on EMD and ADHD, the different clinical profile pattern of ICD disorders for EMD and ADHD disorders suggest an independent etiology. Profiling comorbidity represents a novel approach to understanding disease and etiology.