Epidemiology of Anxiety Disorders in the Australian General Population: Findings of the 2007 Australian National Survey of Mental Health and Wellbeing

Abstract

Objective: The aims of this study were to report 12-month and lifetime prevalence for anxiety disorders in the Australian general population, identify sociodemographic and clinical correlates of anxiety disorders, and report the rates of comorbidity among anxiety, affective, and substance use disorders across the lifespan. Method: The 2007 National Survey of Mental Health and Wellbeing was a nationally representative, face-to-face household survey of 8841 (60% response rate) community residents aged between 16 and 85 years. Diagnoses for anxiety, affective and substance use disorders were made according to the DSM-IV using the World Mental Health Survey Initiative version of the Composite International Diagnostic Interview. Results: 12-month and lifetime prevalence of anxiety disorders were 11.8% and 20.0%, respectively. Anxiety disorders had a similar median age of onset (19 years) compared to substance use disorders (20 years), but earlier than affective disorders (34 years). Social phobia was the earliest onset anxiety disorder (median 13 years), with generalized anxiety disorder the latest (median 33 years). Significant correlates of the presence of anxiety disorders included being female, single, not in the labour force, in the middle age groups, not having post-graduate qualifications, having a comorbid physical condition, and having a family history of mental disorders. Being in the oldest age ranges and being born in another non-English speaking country were associated with lower odds of having an anxiety disorder. Body mass index was not associated with the presence of an anxiety disorder. Anxiety disorders were highly comorbid, particularly with major depression, dysthymia, and alcohol dependence. Comorbidity with substance use disorders reduced with age. Comorbidity with affective disorders was high across the lifespan. Conclusions: Anxiety disorders are common, can have an early onset, and are highly comorbid. Prevention, early detection, and treatment of anxiety disorders should be a priority.