The Effects of Gait Speed and Psychomotor Speed on Risk for Depression and Anxiety in Older Adults with Medical Comorbidities

Background/objectives: Gait speed and psychomotor speed slow with age and may predict neuropsychiatric disease such as depression and anxiety. We explored the relative predictive values of gait speed, psychomotor slowing, and a composite index of these two measures on time to new episode depression or anxiety in older adults at risk for these common psychiatric conditions.

Design: Randomized controlled prevention trial with 15-month follow-up.

Setting: University-based late-life mental health research clinic.

Participants: Two hundred thirteen individuals, age 60+ years, with subsyndromal symptoms of depression or anxiety and one of the following risk factors for these common conditions: mild cognitive impairment, knee osteoarthritis, or disabilities requiring home-based care.

Intervention: Participants in each of the risk factor groups were randomized to a depression-specific preventive intervention or usual care.

Measurements: Gait speed: 4-m walk test from the Short Physical Performance Battery. Psychomotor speed: Coding task of the Repeatable Battery for the Assessment of Neuropsychological Status. We created a composite index of slowing by determining whether participants exceeded established cut-offs for slow performance in both gait speed (≤0.8 m/s) and psychomotor speed (<7 on the coding task). Time to new onset syndromal depression/anxiety was measured using research diagnostic criteria.

Results: Fifty-four participants developed syndromal depression/anxiety (19.5%) over the course of 15 months. Participants with slowing in both areas were over twice as likely to experience new onset depression/anxiety (hazard ratio (HR) = 2.11; 95% confidence interval (CI) = 1.02-4.40, P = .046) compared to participants with no slowing in either area. Slowed gait (HR = 1.88; 95% CI = 0.992-3.55; P = .052) or slowed psychomotor speed (HR = 0.60; 95% CI = 0.14-2.58; P = .488) alone did not increase risk for depression/anxiety.

Conclusion: Evaluating both gait and psychomotor speed in older adults with medical comorbidities and sub-syndromal depression may predict incident mental illness and inform prevention planning. Future research is needed to validate our observations and explore shared neurobiological mechanisms that explain this elevated risk.