Yi DaiFollow

Date of Award

January 2022

Document Type


Degree Name

Master of Public Health (MPH)


School of Public Health

First Advisor

Maria Ciarleglio

Second Advisor

Anita Wang


Objective: This observational study aimed to describe the long-term treatment effect for Major Depressive Disorder (MDD). We aimed to compare the effect of the two most used antidepressant categories, SSRI and SNRI, as the initial treatment and to summarize the dynamic treatment strategies for MDD in the three-year follow-up in practice and compare the treatment effect. We hypothesized that there existed some strategies that made a higher probability of remission or stable long-term maintenance over a three-year follow-up period. Methods: 82641 Veteran patients who met specific inclusion/exclusion criteria were enrolled and their treatment records between 2010 and 2017 were analyzed. Patients were summarized in terms of demographic, co-morbidities, and treatment history. The initial single treatment, SSRI vs. SNRI, was compared with adjusted survival analysis. The dynamic treatment strategies were extracted from the clinical data and analyzed with the multi-state model. Results: 86% of patients started with SSRI and 14% used SNRI. Adjusted with all baseline characteristics, two antidepressants didn’t have a significant difference in treatment effect on time to changing the treatment. Overall, 45% of patients tried the second category of the drug in three years, 28% moved to the third step of treatment, and 14% had more frequent changes. Only 6% of patients had remission (PHQ-9 score < 5) in the three-year period. Patients stayed in their initial treatment for the longest time, which was 10 months for one treatment period and 16 months per patient in three years on average, compared to the later treatment if existed. The treatment strategies were complex in VA, and, for patients in each current treatment, some strategies had higher probability to be the next step compared to others. Conclusions: VA treatment records provided important information to have an overall idea of the dynamic treatment regimens for MDD. Some treatment strategies are preferred in practice, while the actual treatment effect compared to others was still unclear and needs more study.


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