The number of adults aged 65 years or older who take antidepressants more than doubled during the past 2 decades, despite little change in the number of seniors diagnosed with depression, new research shows.

With an increase in the use of antidepressants, it was hoped that the prevalence of depression would decline significantly, "but we haven't observed that in our study," lead author Antony Arthur, PhD, University of East Anglia, Norwich, United Kingdom, told Medscape Medical News.

The study was published online October 7 in the British Journal of Psychiatry.

Appropriate Prescribing?

Data for the analysis came from the Cognitive Function and Ageing Studies, conducted between 1991 and 1993 and between 2008 and 2011.

Researchers interviewed more than 15,000 adults aged 65 years or older in England and Wales to see whether the prevalence of depression and antidepressant use had changed.

They used a standardized interview process to determine the presence or absence of symptoms of depression and then applied diagnostic criteria to determine whether the participant had "case level" depression ― a level of depression more severe than that characterized by minor mood symptoms, such as loss of energy, interest, or enjoyment.

Between the two comparable groups of persons interviewed 20 years apart, the prevalence of depression fell only slightly ― from 7.9% in the earlier period to 6.8% in the later period. However, the proportion of adults taking antidepressants jumped from 4.2% in the early period to 10.7% 2 decades later.

The researchers say it is unclear whether the observed increases in treatment reflect overdiagnosis, better recognition and prescribing, or the prescribing of antidepressant medication for conditions other than depression.

Most of those who took antidepressants did not have a diagnosis of depression, and there are several possible explanations for this, Arthur said.

"Sometimes treatment is given for mild depression which falls outside of our definition of depression ― much of the evidence for the effectiveness of antidepressants is for people with moderate or severe depression. Antidepressants are also used to treat other conditions, for example, neuropathic pain and sleep disorders," he said.

Owing to the nature of the study design ― cross-sectional analysis of two cohorts aged 65+ 20 years apart ― "we can't infer that older patients are prescribed antidepressants unnecessarily," Arthur said.

"But we shouldn't be complacent," he added. "Regular review is key to ensure that opportunities to deprescribe where it is safe and sensible to do so are not overlooked."

On the other hand, some patients have depression but are not taking antidepressants.

"Health providers need to be vigilant with this group to discern whether it's unrecognized depression that would be responsive to treatment," said Arthur.

Questions Raised

"This study raises a number of questions that are not easy to answer due to the study design and lack of information about the past history of clinical depression," Ramin Mojtabai, MD, PhD, MPH, professor in the Department of Mental Health at the Johns Hopkins Bloomberg School of Public Health in Baltimore, Maryland, told Medscape Medical News.

His own research suggests that the prevalence of mood and anxiety disorders and symptoms has not decreased, despite substantial increases in the provision of treatment, particularly antidepressants.

That study, published in World Psychiatry in 2017, was based on depression prevalence and antidepressant use data from 1990 to 2015 in Australia, Canada, England, and the United States.

"The quality of antidepressant treatment in community settings remains problematic," said Mojtabai. "Many patients continue on the same medication regimen, although they could benefit from medication adjustment (eg, dose increase, augmentation, switching to other mediations)," he commented.

The study was funded by grants from the Medical Research Council, the UK Department of Health, the Alzheimer's Society, the National Institute for Health Research Clinical Research Network in West Anglia and Trent, and the Dementias and Neurodegenerative Disease Research Network in Newcastle. Arthur and Mojtabai have disclosed no relevant financial relationships.

Br J Psychiatry. Published online October 7, 2019. Abstract

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