Affective and anxiety disorders: prevalence, treatment and antidepressant medication use.

OBJECTIVE

The aim of the present study was to investigate the prevalence and treatment of affective and anxiety disorders in adults in Australia and compare these with the dispensed prescriptions of drugs used to treat these disorders.

METHODS

Analysis was done of the 2007 National Survey of Mental Health and Wellbeing regarding 12 month prevalence and treatment for affective and anxiety disorders and Pharmaceutical Benefits Scheme prescribing data for antidepressants for 2002-2007. The main outcome measures were prevalence and treatment (rates per 1000 population) and antidepressant utilization (defined daily dose 1000 population(-1) day-1) by gender and age (5 and 10 year age groups).

RESULTS

The prevalence and treatment of affective and anxiety disorder are highest in those aged <50, after which it declines rapidly. Rates for both are higher in women than men. Overall antidepressant use increased 41% over the study period (selective serotonin re-uptake inhibitors 44%, venlafaxine 75%). Sertraline held the majority of the market, followed by venlafaxine and citalopram. Utilization of antidepressants had a bimodal distribution with peaks in those aged in their late 50s and early 90s. The peak use of antidepressants was in those aged 90-94 years.

CONCLUSION

There is poor alignment between the prevalence and self-reported treatment of affective and anxiety disorders in the community and the prescribing of medications for these disorders. It appears that older Australians are receiving antidepressant medications for reasons other than the treatment of conditions for which these drugs have marketing approval or for depressive and anxiety symptoms that do not reach the threshold for a diagnosis.