Differentiating DSM-IV Anxiety and Depressive Disorders in the General Population: Comorbidity and Treatment Consequences

OBJECTIVE: To attempt, for the first time, to apply a positive and differential diagnosis process in the general population during interviews using DSM-IV classification to ascertain the profile and occurrence of concomitant mental disorders. METHOD: A representative sample of 1832 individuals aged 15 years or older living in the metropolitan area of Toronto were interviewed by means of telephone interviews. The participation rate was 72.8%. RESULTS: Overall, 13.2% (n = 242) of the sample had either a mood disorder (n = 127; 6.9%) or an anxiety disorder (n = 170; 9.3%) at the time of their interview. The prevalence was higher among women (16.5%) than among men (9.7%), with an odds ratio of 1.8. The comorbidity of mood and anxiety disorders was found in 3% (n = 55) of the sample. Less than one-third of respondents with a mood and/or anxiety disorder were being treated by a physician for a mental disorder. However, these individuals were greater consumers of health care services. Most of them consulted a physician an average of 5 times in the past year. Individuals on medication diagnosed with a mood and an anxiety disorder consulted a physician an average of 12 times in the past year. Only 13% of them were treated with antidepressants and under 9% with anxiolytics. CONCLUSIONS: More than 70% of subjects with a mood disorder also complained of insomnia. With the differential process, 12% of the subjects manifesting a full-fledged anxiety disorder were diagnosed with only a mood disorder because the anxiety occurred only in the course of the mood disorder. About two-thirds of the subjects diagnosed in this study were undiagnosed and untreated by their physician.