Breaking down the boundaries: comorbidity of mental and physical disorders

Original KEYNOTE abstract by Dr Kathleen Merikangas (National Institute of Mental Health, US, Intramural Research Program, Bethesda, USA) on, held at the ESCAP 2013 Congress in Dublin, Wednesday 10th July 2013.

Although there has been substantial information on the associations between mental disorders and specific physical conditions such as anxiety and asthma in both adults and youth, there has been limited information on the broader patterns of associations of these conditions in general population samples. There is substantial impact of mental and physical comorbidity in adults including increased mortality (cancer, COPD, stroke, heart disease), greater health care costs, poorer treatment response, and more functional impairment. The aims of this lecture are to: (1) describe the background and evidence on the patterns and impact of comorbid mental and physical disorders in adults; (2) discuss methodological challenges in investigating mentalphysical comorbidity; (3) present patterns of mental-physical comorbidity in community studies of children; and (4) summarize the clinical significance and impact of mental-physical comorbidity in youth.
Systematic review of the rates, patterns and impact of physical disorders across international community surveys of mental disorders in children and adolescents revealed that there were few studies that collected sufficient information to yield estimates of comorbidity with the most frequent physical disorders in children including allergies, asthma, headache, and gastrointestinal problems. Methodologic challenges in studying this association include the lack of comparability of diagnostic assessment of mental and physical disorder, different associations with disorder subtypes, variation in prevalence periods for disorders, and different sample sources for the medical and psychiatric disorder index probands. Specific results of analyses of the patterns and impact of mental and physical disorders in the National Comorbidity Survey Adolescent Supplement, the National Health Examination and Nutrition Survey in the US and the Neurodevelopmental Genomics project at the University of Pennsylvania (R. Gur et al) will be described. Potential explanations for poorer treatment response and outcome of those with this comorbidity include comorbidity as a general marker of severity, primary or secondary inflammatory/ immune processes underlying one or both conditions, general sleep and appetite disturbances, poorer health behaviors, increased stress reactivity, and/or poorer compliance with treatment.
Keywords: comorbidity, epidemiology, medical disorders, mood disorders, anxiety disorders, behavior disorders, ADHD.

  • Kathleen R. Merikangas

    Portrait of dr Kathleen MerikangasDr Kathleen Ries Merikangas is senior investigator and chief of the Genetic Epidemiology Branch in the intramural research program at the National Institute of Mental Health (NIMH). She received a bachelor’s degree summa cum laude in experimental psychology and music from the University of Notre Dame. She received clinical training through a NIAAA-sponsored master’s program and internship at the Western Psychiatric Institute and Clinic at the University of Pittsburgh School of Medicine, where she continued to conduct clinical research on the Affective Disorders Clinical Research Unit while she pursued a Ph.D. in chronic disease epidemiology from the University of Pittsburgh School of Public Health.

  • Through a Career Development Award from the NIMH, she completed postdoctoral training in population genetics/genetic epidemiology at the Yale University School of Medicine, where she joined the faculty and ultimately became a Professor of Epidemiology and Public Health, Psychiatry and Psychology and the Director of the Genetic Epidemiology Research Unit in the Department of Epidemiology and Public Health. She came to the NIH in 2002 as part of the development of the Porter Neuroscience Research Center.
    Dr Merikangas has authored more than 300 scientific publications and has presented lectures throughout the U.S. and in more than twenty countries. Her work has contributed to both methodology in epidemiology and genetics, including methods for studying causes of comorbidity and the development of the genome-wide association 

  • study approach to detect genes for complex diseases, and to substantive knowledge about comorbidity of mood disorders with substance use disorders, and migraine with mood disorders and stroke. Dr Merikangas has also devoted substantial effort to training activities including mentorship of individuals and directing formal training programs in genetic epidemiology at both Yale and at the NIH. The two major areas of her research in the Intramural Program at the NIMH are population based studies of mental and physical disorders including the first study of mental disorders in a nationally representative sample of youth in the United States, and multigenerational family studies designed to identify the core features and genetic and environmental factors underlying the familial transmission of bipolar spectrum disorders and co-transmission of mood and anxiety disorders and migraine.