Why do increasing numbers of Australians require disability support pensions for psychiatric conditions, when the prevalence of underlying mental health symptoms has not changed?

THE prevalence of common mental disorders (CMDs) such as depression and anxiety in Australia was fairly stable between 2001 and 2014, but the number of working–age individuals receiving a disability support pension (DSP) for psychiatric conditions increased by about 50% over the same period, according to new research published in the Medical Journal of Australia.

Associate Professor Samuel Harvey from Black Dog Institute and the School of Psychiatry at the University of NSW, and colleagues from UNSW, the Black Dog Institute, the University of Melbourne, and three Norwegian institutions, analysed data from five successive Australian national health surveys and national data on DSP recipients.

“There is a common belief that we are in the midst of a mental health epidemic, with ever increasing rates of depression and anxiety,” said Associate Professor Harvey, the lead author of the study. “The good news is that, based on the latest national health survey data, this doesn’t appear to the case in Australia.

“Our study found there was no change in the prevalence of probable depression or anxiety between 2001 and 2014, and there was a slight but significant decrease in the estimated prevalence of less severe depression and anxiety symptoms over the same period.

Over the same time period, the proportion of the Australian population receiving DSPs for psychiatric conditions increased by 51%, equivalent to one additional DSP for mental ill health for every 182 working–age Australians.

“These two results leave us with a fascinating conundrum,” said Associate Professor Harvey. “Why does Australia have increasing numbers of individuals requiring DSP for psychiatric conditions, when the prevalence of underlying mental health symptoms has not changed?”

Associate Professor Harvey and his colleagues propose four possible explanations for this discrepancy:

• Practitioners may now be more inclined to apply the diagnostic labels of psychiatric disorders, or to identify the main cause of disability as a mental disorder even when presented together with a physical disorder. “The corresponding decrease in the proportion of disability benefits for some other common comorbid conditions, such as musculoskeletal problems, indirectly supports this possibility,” the authors wrote.
• A range of policy initiatives in Australia have attempted to connect people on income support with employment opportunities, an unintended consequence of which may have been to “transfer people with mental health problems from more work–focused income support payments to schemes such as the DSP”.
• It is possible that workplaces in Australia are becoming less tolerant of CMDs because of the changing nature and demands of contemporary work, or social stigmas, forcing people with CMDs to leave the workforce.
• The incidence of CMDs may be increasing, but has been offset by increasing use of treatments that effectively control symptoms without having a substantial effect on functional outcomes for patients.

Associate Professor Harvey concludes: “Regardless of the underlying cause of this discrepancy, what is clear is that while Australia has had some success in containing rates of mental health conditions over the last decade, common mental health problems such as depression and anxiety are continuing to have a major impact on the working–age population and are creating an increasing cost for the individuals, their employers and for society at large”.