Treating Depression as Chronic Brings Positive Results

Optimal treatment of depression using cognitive-behavioral therapy and antidepressant medication as part of a long-term strategy that views the disorder as a chronic, rather than an episodic, illness could significantly diminish the overall disease burden of depression.

This finding is from a novel study of avertable disease burden of major depression in Australia reported in the November Archives of General Psychiatry. The researchers used secondary analysis of mental health survey data in Australia, statistical models of the natural history of depression, and meta-analyses of data on effectiveness of therapy to estimate the burden of disease that might be averted using optimal, guideline-recommended practices.

“Our results strongly support longerterm treatment strategies for depression,” said lead author Gavin Andrews, M.D., and colleagues.“ The main reasons for this favorable outcome are that maintenance treatment prevents relapses and that relapses that do occur are being treated from the start.

“Similarities in community survey findings on the epidemiology of major depression in the United States and Australia and the predominantly United States studies on the impact of treatments used in our model make it likely that our results also have relevance to depression in the United States.”

Andrews is with the clinical research unit for anxiety and depression at the University of New South Wales in Sydney.

Andrews and colleagues estimated that current episodic treatment patterns avert 9 percent of the burden experienced by those in contact with health services. But optimal treatment of an episode with cognitive-behavioral therapy could avert 28 percent of the disease burden, and 24 percent with medications, they said.

During the five years after an episode of major depression, current episodic treatment patterns would avert 13 percent of “disability adjusted life years (DALY),” an indicator of the time lived with a disability and the time lost due to premature mortality, whereas maintenance drug treatment could avert 50 percent, and maintenance CBT could avert 52 percent.

“Because the vast majority of people with depression experience multiple episodes over a lifetime and are particularly prone to relapses shortly after an index episode, there are convincing arguments for treating all depression as a chronic disorder and not just those with recurrent or more severe episodes as recommended in current treatment guidelines,” the researchers said.

Darrel Regier, M.D., M.P.H., explained that the study is an unusually sophisticated approach that draws on a “burden of disease” model used by the World Health Organization in calculating the global burden of psychiatric illness.

In that model, the component of the DALY relating to duration of time lost due to premature mortality is calculated with model life tables using standard expected years of life lost; the reduction in physical capacity due to morbidity is measured using disability weights.

The DALY is then combined with prevalence data and—in Andrews' study—with information on effectiveness of current and optimal treatments to yield estimates of avertable burden of disease.

Regier, who is executive director of the American Psychiatric Institute for Research and Education and director of APA's Division of Research, noted that Andrews has published similar papers on schizophrenia and anxiety disorders and spoke last year to the APA Assembly about his research.

“This is an enormously complex set of measurements that he has brought to bear on the subject in an extremely creative way,” Regier said. “It is a wonderfully comprehensive approach to looking at the true public health challenge of improving mental health in a population.”

Major depression is the largest single cause of nonfatal disease burden in Australia, responsible for 6.2 percent and 9.8 percent of years lived with disability in men and women, respectively. In 2000 an estimated 555 male and 198 female deaths by suicide were attributable to major depression in Australia.

The study, “The Burden of Major Depression Avoidable by Longer-Term Treatment Strategies,” is posted online at<http://archpsyc.ama-assn.org/cgi/content/full/61/11/1097?>.▪

Arch Gen Psychiatry 2004 61 1097