A randomized, double-blind, placebo-controlled trial of antidepressants in Parkinson disease

Abstract

Objective: To evaluate the efficacy and safety of a selective serotonin reuptake inhibitor (SSRI) and a serotonin and norepinephrine reuptake inhibitor (SNRI) in the treatment of depression in Parkinson disease (PD).

Methods: A total of 115 subjects with PD were enrolled at 20 sites. Subjects were randomized to receive an SSRI (paroxetine; n = 42), an SNRI (venlafaxine extended release [XR]; n = 34), or placebo (n = 39). Subjects met DSM-IV criteria for a depressive disorder, or operationally defined subsyndromal depression, and scored >12 on the first 17 items of the Hamilton Rating Scale for Depression (HAM-D). Subjects were followed for 12 weeks (6-week dosage adjustment, 6-week maintenance). Maximum daily dosages were 40 mg for paroxetine and 225 mg for venlafaxine XR. The primary outcome measure was change in the HAM-D score from baseline to week 12.

Results: Treatment effects (relative to placebo), expressed as mean 12-week reductions in HAM-D score, were 6.2 points (97.5% confidence interval [CI] 2.2 to 10.3, p = 0.0007) in the paroxetine group and 4.2 points (97.5% CI 0.1 to 8.4, p = 0.02) in the venlafaxine XR group. No treatment effects were seen on motor function.

Conclusions: Both paroxetine and venlafaxine XR significantly improved depression in subjects with PD. Both medications were generally safe and well tolerated and did not worsen motor function.

Classification of evidence: This study provides Class I evidence that paroxetine and venlafaxine XR are effective in treating depression in patients with PD.

Figure 1. Participant flow

HAM-D = Hamilton Rating Scale for Depression.

Figure 2. Adjusted mean change in Hamilton Rating Scale for Depression (HAM-D) score over time by treatment group

Mean changes are adjusted for center and the baseline HAM-D score using a repeated-measures analysis of covariance model. Error bars represent 1 SEM.