THE IMPACT OF SSRI TREATMENT OF MAJOR DEPRESSION ON GAIT AND POSTURAL STABILITY IN OLDER ADULTS: A PILOT FEASIBILITY STUDY

Abstract

Introduction Falls are a common and potentially catastrophic event in older adults, and mortality due to falls is increasing. Older adults with psychiatric and cognitive disorders are at particularly high risk of falls and are at high risk for the negative consequences of falls, including fear of falling, functional decline, injury and dependence. Geriatric psychiatrists are confronted with a tension between the treatment of distressing psychiatric symptoms and disorders in older adults, and the concern about increasing the risk for falls. In particular, antidepressants are among the most commonly prescribed drugs in older adults, and the relationship between these drugs and falls events has been established through epidemiological studies. However, these studies are confounded by indication, in that depression itself is a known risk factor for falls. To date, little is known about the specific mechanisms of SSRI-related falls. The objective of this study was to determine the feasibility of a longitudinal study of the impact of sertraline treatment on gait and postural stability, and to establish the effect sizes for a fully powered study. Methods We completed a 12-week open label pilot observational study of sertraline for major depression in older adults. This study used instrumented walkway to measure features of gait stability and FallsLab (a 2-D motion platform) to measure postural stability and balance recovery reactions. Gait and dynamic stability of older adults with depression (n=12) at baseline and 3,6, and 12 weeks after initiation of sertraline was compared to the performance of a group of healthy controls (n=8). Results There were consistent baseline differences between depressed and control participants in their gait and postural stability, which persisted despite improvement in depressive symptoms. Short-term changes in gait stability were observed at 3 weeks after starting sertraline, which resolved by 6 weeks. Depressed individuals on sertraline became less cautious in their gait over time, as measured by decreased double stance time, and had worse standing postural sway. There were no changes over time with treatment in standing or dynamic postural stability. Healthy control and depressed participants showed some degree of practice effect in assessments over time. From the perspective of feasibility, depressed older adults with fear of falling did not tolerate the perturbations, with a high withdrawal rate in that group. Conclusions There are subtle changes in gait and stability observable after treatment with antidepressants, but important methodological issues need to be addressed, including practice effects with repeated assessments and development of an adequately challenging balance recovery paradigm which is acceptable to depressed older adults. This research was funded by: Dean's Fund, University of Toronto; UHN psychiatric consultants research grant; Walter and Maria Schroeder Institute for Brain Innovation and Recovery.