Nine-month predictors and outcomes of SSRI antidepressant continuation in primary care

Abstract

Background: This study aimed to identify the predictors and outcomes of SSRI antidepressant continuation, discontinuation and switching over a 9-month period of naturalistic observation.

Methods: Primary care patients (n=573) with physician-diagnosed depression from 37 practices were randomized to an open-label trial of one of three selective serotonin reuptake inhibitors (SSRIs) managed in their primary care setting. Psychiatric characteristics and treatment course were assessed at baseline and at 1, 3, 6 and 9 months after medication initiation.

Results: Nineteen percent of patients switched SSRIs, which occurred significantly sooner than discontinuation (median: 41 vs.100 days). Time to discontinuation was primarily explained by baseline patient skepticism about taking an antidepressant (62% increase in discontinuation risk). In contrast, time to switch was associated with greater impairment at baseline and lesser improvement in impairment during the first month on medication. Patients who discontinued were significantly less likely to be depressed 9 months after starting medication than those who either continued or switched medication, and were less symptomatic and impaired than patients who switched.

Conclusions: Baseline impairment may increase the risk for SSRI antidepressant switching. Additionally, patient skepticism about antidepressants predicts early SSRI discontinuation and may predict rapid recovery. Intent-to-treat analyses in nonrandomized clinical trials may paradoxically inflate antidepressant effect sizes.