Escitalopram for older adults with generalized anxiety disorder: a randomized controlled trial

Abstract

Context: Generalized anxiety disorder (GAD) is one of the most common psychiatric disorders in older adults; however, few data exist to guide clinicians in efficacious and safe treatment. Selective serotonin reuptake inhibitors (SSRIs) are efficacious for younger adults with GAD, but benefits and risks may be different in older adults.

Objective: To examine the efficacy, safety, and tolerability of the SSRI escitalopram in older adults with GAD.

Design, setting, and participants: A randomized controlled trial in primary care practices and related specialty clinics in Pittsburgh, Pennsylvania, of 177 participants aged 60 years or older with a principal diagnosis of GAD randomized to receive either escitalopram or placebo and conducted between January 2005 and January 2008.

Interventions: Twelve weeks of 10 to 20 mg/d of escitalopram (n = 85) or matching placebo (n = 92).

Main outcome measures: Cumulative response defined by Clinical Global Impressions-Improvement score of much or very much improved; time to response; and anxiety and role functioning changes measured by the Clinical Global Impressions-Improvement scale, Hamilton Anxiety Rating Scale, Penn State Worry Questionnaire, Late-Life Function and Disability Instrument activity limitations subscale, and the role-emotional impairment and social function subscales of the Medical Outcome Survey 36-item Short Form.

Results: In the primary analytic strategy in which participants (n = 33) were censored at the time of dropout, mean cumulative response rate for escitalopram was 69% (95% confidence interval [CI], 58%-80%) vs 51% (95% CI, 40%-62%) for placebo (P = .03). A conservative intention-to-treat analysis showed no difference in mean cumulative response rate between escitalopram and placebo (57%; 95% CI, 46%-67%; vs 45%; 95% CI, 35%-55%; P = .11). Participants treated with escitalopram showed greater improvement than with placebo in anxiety symptoms and role functioning (Clinical Global Impressions-Improvement scale: effect size, 0.93; 95% CI, 0.50-1.36; P < .001; Penn State Worry Questionnaire: 0.30; 95% CI, 0.23-0.48; P = .01; activity limitations: 0.32; 95% CI, 0.01-0.63; P = .04; and the role-emotional impairment and social function: 0.96; 95% CI, 0.03-1.90; P = .04). Adverse effects of escitalopram (P < .05 vs placebo) were fatigue or somnolence (35 patients [41.1%]), sleep disturbance (12 [14.1%]), and urinary symptoms (8 [9.4%]).

Conclusions: Older adults with GAD randomized to escitalopram had a higher cumulative response rate for improvement vs placebo over 12 weeks; however, response rates were not significantly different using an intention-to-treat analysis. Further study is required to assess efficacy and safety over longer treatment durations.

Trial registration: clinicaltrials.gov Identifier: NCT00105586.

Figure 1. Flow of Patients Through the Trial

GAD indicates generalized anxiety disorder.

Figure 2. Kaplan-Meier Survival Curve With Escitalopram or Placebo

Overall time to response is not different between groups. Subgroup analysis of 2 intervals (before week 4 and week 4 to 12) shows no difference between treatments initially (P=.43), a crossing over of the curves at week 6, and then subsequent superiority of escitalopram (P=.01).

Figure 3. Improvements in Anxiety Symptoms and Disability and Quality of Life Measures

Effect sizes are expressed as Cohen d where 0.2=small, 0.5=medium, and 0.8=large. Activity limitations is a subscale of the Late-Life Function and Disability Instrument. SF-36 role-emotional impairment and SF-36 social function are the role-emotional impairment and social function subscales of the Medical Outcome Survey 36-item Short Form.

Figure 4. Rates of Overall Self-reported Adverse Effects Over Time in the Escitalopram and Placebo Groups

Error bars indicate SE. Proportions did not significantly differ at any point except at week 6 (escitalopram vs placebo, P=.007), which was the visit after the titration to 20 mg/d.