Comorbid Depression and Anxiety in Later Life: Patterns of Association, Subjective Well-being, and Impairment John Cairney, Ph.D., Laurie M. Corna, M.Sc., Ph.D. Candidate, Scott Veldhuizen, B.A., Nathan Herrmann, M.D., David L. Streiner, Ph.D. Objective: Very little epidemiological work has examined comorbidity between depression and anxiety disorders in community-dwelling older adults, despite the fact these disorders are known to co-occur in younger adults and that this co-occurrence is associated with greater clinical severity. In this study, the authors examine psychiatric comorbidity and associated impairment of four disorders (major depression, panic disorder, social phobia, and agora- phobia) in a community-based sample of adults aged 55 and older. Setting: Population- based sample of older adults (N = 12,792) from the Canadian Community Health Survey— Mental Health and Well-Being (CCHS 1.2). Method: The World Mental Health Composite International Diagnostic Interview was used to identify cases of 12-month disorder. Descrip- tive analysis and regression analysis is used to examine patterns of association between disorders and related impairment. Results: Among adults aged 55 years and older, 4.4% met the criteria for at least one disorder and 0.8% had two or more. Social phobia was the most common comorbid disorder among respondents with depression, and depression was the most common comorbid disorder among respondents with any of the anxiety disorders. Respondents who report comorbid disorders reported significantly lower well-being and greater impairment. Conclusion: Although comorbidity between physical health conditions and depression, and between dementias and depression, are well documented among older adults, these results suggest that comorbid depression and anxiety are also prevalent in later life. The significant impact of comorbidity on function and well-being underlines the need to screen for comorbid disorders in this population. (Am J Geriatr Psychiatry 2008; 16:201–208) Key Words: Psychiatric comorbidity, anxiety and depression, older adults, impairment U ntil recently, population-based epidemiological studies of psychiatric disorder and impairment have tended to exclude older adults, largely because influential Diagnostic and Statistical Manual of Mental Disorders, Third Edition (DSM–III) generation studies found that most major disorders were uncommon in Received May 3, 2007; revised August 1, 2007; accepted August 7, 2007. From the Health Systems Research and Consulting Unit (JC, SV), Centre for Addiction and Mental Health; Departments of Psychiatry (JC, NH, DLS) and Public Health Sciences (JC, LMC), Sunnybrook and Women’s College Health Sciences Centre (NH), Baycrest Centre for Geriatric Care (DLS), University of Toronto, Toronto, ON. A version of this paper was presented at American Psychiatric Association Annual Meeting, May 25, 2006, Toronto, ON. Send correspondence and reprint requests to Dr. John Cairney, Health Systems Research and Consulting Unit, Centre for Addiction and Mental Health, Departments of Psychiatry and Public Health Science, University of Toronto, 33 Russell Street, Toronto, ON M5S 2S1. e-mail: john_cairney@camh.net © 2008 American Association for Geriatric Psychiatry Am J Geriatr Psychiatry 16:3, March 2008 201