Depression creates significant physical, psychological, and social burdens for all age groups. Depression can lead to decreased daily functioning, the onset of chronic illnesses, mortality, and increased use of health care services. Older adults are not immune to depressive symptoms or its negative effects, and may have poorer outcomes than younger age groups, according to a new study published in the British Medical Journal (BMJ).

Researchers conducted a longitudinal cohort study of more than 200 patients aged 55 years or older that had a diagnosis of major depressive disorder, using criteria in the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV). The patients were collected from 32 general practice outpatient clinics in the Netherlands. Depression was measured at baseline and at 6-month intervals using structured diagnostic interviews and self-rating scales.

Major depressive episodes in this population lasted an average of 18 months, compared to an average of 6 months in most other age groups. Only 35% of patients were considered recovered from the depression after 1 year. At 2 years, 60% of patients were recovered. After 3 years, 68% of patients were recovered. Predictors of poor prognosis included more severe depression, family history of depression, and decreased physical functioning. In this study group, nearly 30% of the participants reported a family history of depression, and more than 70% reported previous depressive episodes in their personal history. During the 3-year follow-up period, only 37% of the patients were treated for depression. (At the beginning of the study, 40% of patients were receiving treatment for depression.) Surprisingly, no association was found between treatment for depression and recovery, though treatments for depression are most often effective in older adults. The researchers noted that the patients with more severe depressive symptoms were more likely to receive treatment.

While these results indicate a long recovery time and overall poor prognosis for older adults with depression, these results for outpatients are significantly better than the outcomes reported for inpatients with depression. One study reported as few as 13% of patients recovered from depressive episodes after 1 year. Notably, inpatients often have functional limitations, which was an indicator of poor prognosis in the current study. Other predictors of poor depression outcomes in older adults have been reported in a handful of studies: race, psychiatric functioning, and social support.

The current study examined patients with a diagnosis of major depressive disorder, but many older patients suffer from depressive symptoms that do not meet traditional diagnostic criteria, although clinically significant and possibly disabling to their daily life. Patients with so-called subsyndromal depression are common, and their symptoms are not as severe as those consistent with major or minor depression. However, subsyndromal depression symptoms often worsen over time, and develop into major depression. These patients are often undiagnosed and untreated, and their prognosis is generally considered poor.

Most researchers practicing in the area of depression and older adults agree that therapeutic intervention should be targeted at patients with the highest risk of poor outcomes. With an aging population, it may be impossible to treat every older adult with depressive symptoms. However, primary care clinicians should recognize the symptoms of depression in older adults, from subsyndromal depression to major depression, and attempt to modify risk factors such as social support or functional status to improve the outcome of a potential depressive episode.

References

Cui X, Lyness JM, Tang W, Tu X, Conwell Y. Outcomes and predictors of late-life depression trajectories in older primary care patients. Am J Geriatr Psychiatry. May 2008;16(5):406-415.

Els Licht-Strunk, Aartjan T.F. Beekman, Marten de Haan, Harm W.J. van Marwijk (2009). The prognosis of undetected depression in older general practice patients. A one year follow-up study Journal of Affective Disorders, 114 (1-3), 310-315 DOI: 10.1016/j.jad.2008.06.006

E Licht-Strunk, H W J Van Marwijk, T Hoekstra, J W R Twisk, M De Haan, A T F Beekman (2009). Outcome of depression in later life in primary care: longitudinal cohort study with three years’ follow-up BMJ, 338 (feb02 1) DOI: 10.1136/bmj.a3079

Jeffrey M. Lyness, Benjamin P. Chapman, Joanne McGriff, Rebecca Drayer, Paul R. Duberstein (2008). One-year outcomes of minor and subsyndromal depression in older primary care patients International Psychogeriatrics, 21 (01) DOI: 10.1017/S1041610208007746

Jeffrey M. Lyness, JaeHyun Kim, Wan Tang, Xin Tu, Yeates Conwell, Deborah A. King, Eric D. Caine (2007). The Clinical Significance of Subsyndromal Depression in Older Primary Care Patients American Journal of Geriatric Psychiatry, 15 (3), 214-223 DOI: 10.1097/01.JGP.0000235763.50230.83