Objective: To compare health care resource utilization and costs of Major Depressive Disorder (MDD) adult patients treated with escitalopram 10mg who increase to 20mg vs. those who were switched to a SNRI. Methods: Adult MDD patients initiated on escitalopram 10mg who either increased to 20mg escitalopram or switched to a SNRI were identified in the IHCIS National Managed Care Database (2003-2006). Patients who changed therapy within 60 days from escitalopram initiation date (index date) were excluded. Outcomes included rates of hospitalization and emergency visits, number of emergency visits days, and health care costs, and were reported for all cause and MDD-related. All outcomes were estimated over a 3 months period post-therapy change (dose increase or switching) and were descriptively compared between the two groups. Multivariate regression analyses were performed to further adjust for patient demographics, comorbidities and baseline health care resource use. Results: Study samples included 9379 patients who increased escitalopram from 10mg to 20mg and 1215 patients who were switched from 10mg escitalopram to a SNRI. Compared to patients who increased escitalopram dose, SNRI switchers experienced higher rates of MDD-related hospitalizations (RR=1.2, p=0.566), higher rates of MDD-related emergency visit (RR=1.6, p<0.05), and higher number of emergency visit days (RR=1.5, p<0.01) in the 3-month post-therapy change period. Patients who switched to SNRI also had on average $413 higher total costs (p<0.001), which include $390 higher drug costs (p<0.001). Results from multivariate regression analyses were consistent with findings from descriptive analyses. SNRI switchers incurred $430 higher risk-adjusted total costs (p<.0001). Conclusion: Compared to adult MDD patients who increased escitalopram from 10mg to 20mg, patients who switched to a SNRI had more MDD-related emergency visits, as well as higher drug and total health care costs during the 3-month post-therapy change period.